Re: Shared File System Master Slave

[Tim Bain]

Yes, that information is applicable and gives a good overview of the
internals of KahaDB.

Tim

On Mon, Apr 9, 2018, 1:29 AM norinos  wrote:

> I found the following site. Is this helpful for me?
>
> http://www.idevnews.com/images/emailers/110127_ProgressFUSE/WhitePapers/ActiveMQinActionCH05.pdf
>
> --
> Sent from:
> http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
>

Re: Shared File System Master Slave

[norinos]

Hi Tim ! thanks a lot.


> The documentation you linked to is for the AMQ message store, not the 
> KahaDB message store. So if you're using KahaDB as you say, then the page 
> you linked to is irrelevant. 

I finally understood that AMQ and KahaDB are different.

> KahaDB behaves as I described. You only risk losing messages that have not 
> yet been accepted (i.e. you don't risk losing anything). If I recall 
> correctly, the only thing that's flushed to disk periodically is the
> index, 
> and that can be rebuilt from the raw journal files so there's no risk of 
> data loss, just a slower broker startup. 

I feel relieved that it seems there is no risk.


I found the following site. Is this helpful for me?
http://www.idevnews.com/images/emailers/110127_ProgressFUSE/WhitePapers/ActiveMQinActionCH05.pdf





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Re: Shared File System Master Slave

[Tim Bain]

The documentation you linked to is for the AMQ message store, not the
KahaDB message store. So if you're using KahaDB as you say, then the page
you linked to is irrelevant.

KahaDB behaves as I described. You only risk losing messages that have not
yet been accepted (i.e. you don't risk losing anything). If I recall
correctly, the only thing that's flushed to disk periodically is the index,
and that can be rebuilt from the raw journal files so there's no risk of
data loss, just a slower broker startup.

Tim

On Sun, Apr 8, 2018, 10:06 PM norinos  wrote:

> As you say, I'm using KahaDB.
>
> > You asked whether subscriptions would be on the new master, and the
> answer
> > depends on whether the subscription was durable. If it was a durable
> > subscription, the subscription information is persisted and the
> > subscription will be in the same state on the new master, even if the
> > client doesn't immediately reconnect. If the subscription is not durable,
> > then it will be recreated when the client reconnects to the new master,
> so
> > any messages that were unconsumed at the time the original master went
> > down
> > and any messages sent before the client reconnects will be lost for that
> > subscriber.
>
> I'm using durable subscription.
> So, I understand that clients can receive the message without problems
> when switching from master to slave.
>
>
> Please tell me a little more.
>
> ActiveMQ insert cache index into the reference store for performance at
> checkpoint interval.
>
> If master goes down, it seems that chache index can not insert.
> So reference store is not up-to-date.
>
> In this case, if I startup up ActiveMQ, Is the reference store updated at
> the start-up phase?
>
>
>
>
> --
> Sent from:
> http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
>

Re: Shared File System Master Slave

[norinos]

As you say, I'm using KahaDB.

> You asked whether subscriptions would be on the new master, and the answer 
> depends on whether the subscription was durable. If it was a durable 
> subscription, the subscription information is persisted and the 
> subscription will be in the same state on the new master, even if the 
> client doesn't immediately reconnect. If the subscription is not durable, 
> then it will be recreated when the client reconnects to the new master, so 
> any messages that were unconsumed at the time the original master went
> down 
> and any messages sent before the client reconnects will be lost for that 
> subscriber.

I'm using durable subscription.
So, I understand that clients can receive the message without problems
when switching from master to slave.


Please tell me a little more.

ActiveMQ insert cache index into the reference store for performance at
checkpoint interval.

If master goes down, it seems that chache index can not insert.
So reference store is not up-to-date.

In this case, if I startup up ActiveMQ, Is the reference store updated at
the start-up phase?




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Re: Shared File System Master Slave

[Tim Bain]

The AMQ store is not widely used these days. You'll probably be using the
KahaDB store: activemq.apache.org/kahadb.html

As you said, if there is any content that has not been flushed to disk, it
will be lost when the master goes down. However, unless you've manually
set enableJournalDiskSyncs to false, you're not going to lose any messages
whose receipt has been confirmed by the broker. (Any messages lost will be
messages the broker has not yet confirmed receipt of.)

When the slave broker attempts to become active, it will read the data
files and begin serving clients.

You asked whether subscriptions would be on the new master, and the answer
depends on whether the subscription was durable. If it was a durable
subscription, the subscription information is persisted and the
subscription will be in the same state on the new master, even if the
client doesn't immediately reconnect. If the subscription is not durable,
then it will be recreated when the client reconnects to the new master, so
any messages that were unconsumed at the time the original master went down
and any messages sent before the client reconnects will be lost for that
subscriber.

Tim

On Fri, Apr 6, 2018, 1:54 AM norinos <tainookasir...@gmail.com> wrote:

> I am planning to use Shared File System Master Slave.(I use AcitveMQ
> 5.13.1)
> http://activemq.apache.org/shared-file-system-master-slave.html
>
> With this system, even though master(#1)'s process goes down due to
> trouble,
> I think that ActiveMQ can be continuously used in slave(#2) process.
>
> I have a question.
>
> http://activemq.apache.org/amq-message-store.html
>
> According to the above documentation, MQ's memory cache periodically
> inserted into the reference store(db.data).
>
> If master(#1) goes down, memory cache cannot insert.
> It seems that the reference sotre index does not match the Data Logs.
>
> At this time, can #2(New master) start normally ?
> If not, What kind of trouble will occur ?
> For example, Subscribed messages will be subscribe agein.
>
>
>
>
>
> --
> Sent from:
> http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
>

Shared File System Master Slave

[norinos]

I am planning to use Shared File System Master Slave.(I use AcitveMQ 5.13.1)
http://activemq.apache.org/shared-file-system-master-slave.html

With this system, even though master(#1)'s process goes down due to trouble, 
I think that ActiveMQ can be continuously used in slave(#2) process.

I have a question. 

http://activemq.apache.org/amq-message-store.html

According to the above documentation, MQ's memory cache periodically
inserted into the reference store(db.data).

If master(#1) goes down, memory cache cannot insert.
It seems that the reference sotre index does not match the Data Logs.

At this time, can #2(New master) start normally ?
If not, What kind of trouble will occur ?
For example, Subscribed messages will be subscribe agein.





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Shared File System Master Slave

[norinos]

I am planning to use Shared File System Master Slave.(I use AcitveMQ 5.13.1)
http://activemq.apache.org/shared-file-system-master-slave.html

With this system, even though master(#1)'s process goes down due to trouble, 
I think that ActiveMQ can be continuously used in slave(#2) process.

I have a question. 

http://activemq.apache.org/amq-message-store.html

According to the above documentation, MQ's memory cache periodically
inserted into the reference store(db.data).

If master(#1) goes down, memory cache cannot insert.
It seems that the reference sotre index does not match the Data Logs.

At this time, can #2(New master) start normally ?
If not, What kind of trouble will occur ?
For example, Subscribed messages will be subscribe agein.





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Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

It also probably wouldn't be that hard for you to implement a
Zookeeper-based Locker if that sounded more appealing than a SQL database,
since it sounds like you might feel negatively about using an RDBMS.

If you do, we'd love have you donate it back to the community if your
company would allow it; that lets other people benefit from what you
implemented and (key point) means that we - not you - are on the hook for
long-term maintenance.

Tim

On Oct 31, 2017 4:11 PM, "Johan Edstrom"  wrote:

> Using JDBC you can get both.
>
>
>
> 
> 
> 
> 
>  dataSource="#mysql-ds">
> 
> 
> 
> 
> 
> 
> 
> 
>
>
>
>
> > On Oct 31, 2017, at 4:06 PM, akhil  wrote:
> >
> > Hello Everyone ,
> >
> > I just had an issue today with the Active MQ EFS where one of the master
> > lost its mount and two brokers acted as a master master instead of
> complete
> > failover. I have just looked at the pluggable storage lockers but it was
> all
> > giving that locks to JDBC stores not the EFS ones . Is there any
> recommended
> > way of using the correct setting or pluggable lockers for the EFS boxes
> to
> > make a correct failover ? I am using amq version 5.13.4.
> >
> > Please suggest options.
> >
> > Thanks,
> > Akhil.
> >
> >
> >
> > --
> > Sent from: http://activemq.2283324.n4.nabble.com/ActiveMQ-User-
> f2341805.html
>
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[Johan Edstrom]

Using JDBC you can get both.









 










> On Oct 31, 2017, at 4:06 PM, akhil  wrote:
> 
> Hello Everyone , 
> 
> I just had an issue today with the Active MQ EFS where one of the master
> lost its mount and two brokers acted as a master master instead of complete
> failover. I have just looked at the pluggable storage lockers but it was all
> giving that locks to JDBC stores not the EFS ones . Is there any recommended
> way of using the correct setting or pluggable lockers for the EFS boxes to
> make a correct failover ? I am using amq version 5.13.4.
> 
> Please suggest options.
> 
> Thanks,
> Akhil.
> 
> 
> 
> --
> Sent from: http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html

Re: Active MQ Shared File System Master Slave with Elastic File System

[mtod]

I'm working on a similar setup right now can you share your activemq.xml
database config? specificly what class did you use?

I tried the one below but keep getting errors that the class can't be found.










Thanks

Mike




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Re: Active MQ Shared File System Master Slave with Elastic File System

[Christopher Shannon]

The issue has been reopened and will be fixed when someone gets time.  This
would be a relatively easy fix to implement if anyone wants to attempt a
pull request to get it fixed faster.  Version 5.14.1 is being voted on now
but this fix could go into 5.14.2 and 5.15.0.

On Tue, Sep 27, 2016 at 8:50 AM, Tim Bain <tb...@alumni.duke.edu> wrote:

> This issue got closed by Chris Shannon, but I think it would be easy enough
> to add a flag that tells the broker to bypass the total space check that's
> causing problems, so I think we should reopen it.
>
> Tim
>
> On Fri, Sep 23, 2016 at 11:42 AM, wcrowell <william.crow...@roguewave.com>
> wrote:
>
> > Please take a look at the comment I made on:
> > https://issues.apache.org/jira/browse/AMQ-6441
> >
> > I may know what the issue is.  The particular client I am working with is
> > running JDK 7.
> >
> >
> >
> > --
> > View this message in context: http://activemq.2283324.n4.
> > nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> > Elastic-File-System-tp4715818p4716871.html
> > Sent from the ActiveMQ - User mailing list archive at Nabble.com.
> >
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

This issue got closed by Chris Shannon, but I think it would be easy enough
to add a flag that tells the broker to bypass the total space check that's
causing problems, so I think we should reopen it.

Tim

On Fri, Sep 23, 2016 at 11:42 AM, wcrowell <william.crow...@roguewave.com>
wrote:

> Please take a look at the comment I made on:
> https://issues.apache.org/jira/browse/AMQ-6441
>
> I may know what the issue is.  The particular client I am working with is
> running JDK 7.
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818p4716871.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[wcrowell]

Please take a look at the comment I made on:
https://issues.apache.org/jira/browse/AMQ-6441

I may know what the issue is.  The particular client I am working with is
running JDK 7.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

Thanks for following up on this to make sure that one got created.

On Sep 23, 2016 9:34 AM, "wcrowell" <william.crow...@roguewave.com> wrote:

> Thank you!!!  I was going to create one if it had not been done already.
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818p4716853.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[wcrowell]

Did a JIRA issue get created on this?



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Re: Active MQ Shared File System Master Slave with Elastic File System

[wcrowell]

Thank you!!!  I was going to create one if it had not been done already.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

Done: https://issues.apache.org/jira/browse/AMQ-6441

If anyone wants to update the ticket, feel free.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

No not yet, but I will do so now.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

I hadn't heard of anyone using EFS before you asked about it.  That's not
to say that no one has, just that I've got less idea than you do about what
if any pitfalls you might find along the way.

On Sep 21, 2016 10:33 AM, "khokhani" <khokh...@gmail.com> wrote:

> Thanks Tim!  Thanks Justin! for insight on this topic.
>
> I have setup Amazon EFS as LevelDB persistence store and MySql based
> locker.
> All functional and failover testing are positive and message are available
> and delivered without any failure or loss while switching from master to
> slave as well as restarting all brokers.
>
> Is there any other danger using EFS with RDBMS based locker?
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818p4716712.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[khokhani]

Thanks Tim!  Thanks Justin! for insight on this topic.

I have setup Amazon EFS as LevelDB persistence store and MySql based locker.
All functional and failover testing are positive and message are available
and delivered without any failure or loss while switching from master to
slave as well as restarting all brokers.

Is there any other danger using EFS with RDBMS based locker?



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Justin Reock]

Thanks Tim! I recently posted a blog article on this subject, if the user 
community would like some details about the pluggable storage locker 
implementation:  
http://blog.klocwork.com/open-source/pluggable-storage-lockers-for-activemq/

I hope it’s helpful.

-Justin


On 9/2/16, 11:53 PM, "tbai...@gmail.com on behalf of Tim Bain" 
<tbai...@gmail.com on behalf of tb...@alumni.duke.edu> wrote:

It rules out using EFS for your locker implementation, but as Justin said,
pluggable lockers would allow you to put your data into an EFS but use
another mechanism for locking to determine ownership.  But obviously there
would need to be a fix to the code that figures out whether there's enough
space on the volume before that would work.

Tim

On Fri, Sep 2, 2016 at 4:17 PM, ishmeister <ibh...@visibilityltd.com> wrote:

> The issue is perhaps that EFS supports NFS4 but with the following
> limitations:
>
> http://docs.aws.amazon.com/efs/latest/ug/nfs4-unsupported-features.html
>
> In particular: "All locks in Amazon EFS are advisory, which means that 
READ
> and WRITE operations do not check for conflicting locks before the
> operation
> is executed."
>
> Whereas the ActiveMQ docs seem to be quite clear on this matter: "Note 
that
> the requirements of this failover system are a distributed file system 
like
> a SAN for which exclusive file locks work reliably."
>
> http://activemq.apache.org/shared-file-system-master-slave.html
>
> So I guess that effectively rules out using EFS.
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818p4716132.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

It rules out using EFS for your locker implementation, but as Justin said,
pluggable lockers would allow you to put your data into an EFS but use
another mechanism for locking to determine ownership.  But obviously there
would need to be a fix to the code that figures out whether there's enough
space on the volume before that would work.

Tim

On Fri, Sep 2, 2016 at 4:17 PM, ishmeister <ibh...@visibilityltd.com> wrote:

> The issue is perhaps that EFS supports NFS4 but with the following
> limitations:
>
> http://docs.aws.amazon.com/efs/latest/ug/nfs4-unsupported-features.html
>
> In particular: "All locks in Amazon EFS are advisory, which means that READ
> and WRITE operations do not check for conflicting locks before the
> operation
> is executed."
>
> Whereas the ActiveMQ docs seem to be quite clear on this matter: "Note that
> the requirements of this failover system are a distributed file system like
> a SAN for which exclusive file locks work reliably."
>
> http://activemq.apache.org/shared-file-system-master-slave.html
>
> So I guess that effectively rules out using EFS.
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818p4716132.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

The issue is perhaps that EFS supports NFS4 but with the following
limitations:

http://docs.aws.amazon.com/efs/latest/ug/nfs4-unsupported-features.html

In particular: "All locks in Amazon EFS are advisory, which means that READ
and WRITE operations do not check for conflicting locks before the operation
is executed."

Whereas the ActiveMQ docs seem to be quite clear on this matter: "Note that
the requirements of this failover system are a distributed file system like
a SAN for which exclusive file locks work reliably."

http://activemq.apache.org/shared-file-system-master-slave.html

So I guess that effectively rules out using EFS.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Justin Reock]

Be careful of this, in my own load testing the lock state can be lost over EFS 
leading to a “master-master” scenario under heavy load, which can lead to 
journal corruption.  Check out the lease locking pluggable storage locker, 
which is a viable workaround for this problem.

Thanks,
Justin  

On 9/2/16, 2:08 PM, "kor...@gmail.com on behalf of Korny Sietsma" 
<kor...@gmail.com on behalf of ko...@sietsma.com> wrote:

I think all EFS volumes are that size. It's a play-by-usage model - it did
strike me as risky, a runaway process could cost you a lot of money!

On 2 Sep 2016 4:19 p.m., "Tim Bain" <tb...@alumni.duke.edu> wrote:

Was your EFS as large as the one the OP described?  The perceived problem
was that the code couldn't handle a volume that size, not that it couldn't
handle an EFS volume.

On Sep 2, 2016 5:17 AM, "Korny Sietsma" <ko...@sietsma.com> wrote:

> Interesting - we set up ActiveMQ 5.9 successfully on EFS, I'm guessing
> these error messages relate to checks made in later versions of the
> product.
>
> Note that we gave up on this approach - we found that shared filesystem
> master/slave had several problems for us when we tested it with network
lag
> and splits between the master and the EFS file system.
>
> We have since moved to testing LevelDB + Zookeeper, which has been rather
> more reliable in failure scenarios.
>
> - Korny
>
> On 25 August 2016 at 09:16, ishmeister <ibh...@visibilityltd.com> wrote:
    >
> > I'm setting up Active MQ in production with a shared file system
> > master/slave
> > configuration (KahaDB). I've set everything up and mounted the EFS on
> both
> > EC2 instances.
> >
> > When I check the disk free stats I get 8 exabytes for the shared file
> > system:
> >
> > $ df -h
> > eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0%
> > /mnt/efs
> > Unfortunately, ActiveMQ cannot interpret this number:
> >
> > Store limit is 102400 mb (current store usage is 0 mb). The data
> directory:
> > /mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting
to
> > maximum available disk space: -8796093022207 mb
> > Store limit is -8796093022207 mb, whilst the max journal file size for
> the
> > store is: 32 mb, the store will not accept any data when used.
> >
> > However, this has not prevented ActiveMQ from working as far as I can
    > tell.
    > > Is it a problem that "the store will not accept any data when used"?
> >
> >
> >
> > --
> > View this message in context: http://activemq.2283324.n4.
> > nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> > Elastic-File-System-tp4715818.html
> > Sent from the ActiveMQ - User mailing list archive at Nabble.com.
> >
>
>
>
> --
> Kornelis Sietsma  korny at my surname dot com http://korny.info
> .fnord { display: none !important; }
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[Korny Sietsma]

I think all EFS volumes are that size. It's a play-by-usage model - it did
strike me as risky, a runaway process could cost you a lot of money!

On 2 Sep 2016 4:19 p.m., "Tim Bain" <tb...@alumni.duke.edu> wrote:

Was your EFS as large as the one the OP described?  The perceived problem
was that the code couldn't handle a volume that size, not that it couldn't
handle an EFS volume.

On Sep 2, 2016 5:17 AM, "Korny Sietsma" <ko...@sietsma.com> wrote:

> Interesting - we set up ActiveMQ 5.9 successfully on EFS, I'm guessing
> these error messages relate to checks made in later versions of the
> product.
>
> Note that we gave up on this approach - we found that shared filesystem
> master/slave had several problems for us when we tested it with network
lag
> and splits between the master and the EFS file system.
>
> We have since moved to testing LevelDB + Zookeeper, which has been rather
> more reliable in failure scenarios.
>
> - Korny
>
> On 25 August 2016 at 09:16, ishmeister <ibh...@visibilityltd.com> wrote:
>
> > I'm setting up Active MQ in production with a shared file system
> > master/slave
> > configuration (KahaDB). I've set everything up and mounted the EFS on
> both
> > EC2 instances.
> >
> > When I check the disk free stats I get 8 exabytes for the shared file
> > system:
> >
> > $ df -h
> > eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0%
> > /mnt/efs
> > Unfortunately, ActiveMQ cannot interpret this number:
> >
> > Store limit is 102400 mb (current store usage is 0 mb). The data
> directory:
> > /mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting
to
> > maximum available disk space: -8796093022207 mb
> > Store limit is -8796093022207 mb, whilst the max journal file size for
> the
> > store is: 32 mb, the store will not accept any data when used.
> >
> > However, this has not prevented ActiveMQ from working as far as I can
> tell.
> > Is it a problem that "the store will not accept any data when used"?
> >
> >
> >
> > --
> > View this message in context: http://activemq.2283324.n4.
> > nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> > Elastic-File-System-tp4715818.html
> > Sent from the ActiveMQ - User mailing list archive at Nabble.com.
> >
>
>
>
> --
> Kornelis Sietsma  korny at my surname dot com http://korny.info
> .fnord { display: none !important; }
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

Tim,

I contacted AWS tech support and their response was this:

"I've checked with our EFS team to see if there is any EFS-related
workaround they can offer. Unfortunately, they have confirmed that this is
EFS intended behavior and there is no way of mounting a filesystem with
"predetermined size" or change the way it is reported by the OS that they or
myself know of."

The OS in my case was Ubuntu 14.04. 

Korny, thanks for the tips.



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

Was your EFS as large as the one the OP described?  The perceived problem
was that the code couldn't handle a volume that size, not that it couldn't
handle an EFS volume.

On Sep 2, 2016 5:17 AM, "Korny Sietsma" <ko...@sietsma.com> wrote:

> Interesting - we set up ActiveMQ 5.9 successfully on EFS, I'm guessing
> these error messages relate to checks made in later versions of the
> product.
>
> Note that we gave up on this approach - we found that shared filesystem
> master/slave had several problems for us when we tested it with network lag
> and splits between the master and the EFS file system.
>
> We have since moved to testing LevelDB + Zookeeper, which has been rather
> more reliable in failure scenarios.
>
> - Korny
>
> On 25 August 2016 at 09:16, ishmeister <ibh...@visibilityltd.com> wrote:
>
> > I'm setting up Active MQ in production with a shared file system
> > master/slave
> > configuration (KahaDB). I've set everything up and mounted the EFS on
> both
> > EC2 instances.
> >
> > When I check the disk free stats I get 8 exabytes for the shared file
> > system:
> >
> > $ df -h
> > eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0%
> > /mnt/efs
> > Unfortunately, ActiveMQ cannot interpret this number:
> >
> > Store limit is 102400 mb (current store usage is 0 mb). The data
> directory:
> > /mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting to
> > maximum available disk space: -8796093022207 mb
> > Store limit is -8796093022207 mb, whilst the max journal file size for
> the
> > store is: 32 mb, the store will not accept any data when used.
> >
> > However, this has not prevented ActiveMQ from working as far as I can
> tell.
> > Is it a problem that "the store will not accept any data when used"?
> >
> >
> >
> > --
> > View this message in context: http://activemq.2283324.n4.
> > nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> > Elastic-File-System-tp4715818.html
> > Sent from the ActiveMQ - User mailing list archive at Nabble.com.
> >
>
>
>
> --
> Kornelis Sietsma  korny at my surname dot com http://korny.info
> .fnord { display: none !important; }
>

Re: Active MQ Shared File System Master Slave with Elastic File System

[Korny Sietsma]

Interesting - we set up ActiveMQ 5.9 successfully on EFS, I'm guessing
these error messages relate to checks made in later versions of the product.

Note that we gave up on this approach - we found that shared filesystem
master/slave had several problems for us when we tested it with network lag
and splits between the master and the EFS file system.

We have since moved to testing LevelDB + Zookeeper, which has been rather
more reliable in failure scenarios.

- Korny

On 25 August 2016 at 09:16, ishmeister <ibh...@visibilityltd.com> wrote:

> I'm setting up Active MQ in production with a shared file system
> master/slave
> configuration (KahaDB). I've set everything up and mounted the EFS on both
> EC2 instances.
>
> When I check the disk free stats I get 8 exabytes for the shared file
> system:
>
> $ df -h
> eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0%
> /mnt/efs
> Unfortunately, ActiveMQ cannot interpret this number:
>
> Store limit is 102400 mb (current store usage is 0 mb). The data directory:
> /mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting to
> maximum available disk space: -8796093022207 mb
> Store limit is -8796093022207 mb, whilst the max journal file size for the
> store is: 32 mb, the store will not accept any data when used.
>
> However, this has not prevented ActiveMQ from working as far as I can tell.
> Is it a problem that "the store will not accept any data when used"?
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>



-- 
Kornelis Sietsma  korny at my surname dot com http://korny.info
.fnord { display: none !important; }

Re: Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

Thanks Tim. I'll get this up on JIRA soon. 



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Re: Active MQ Shared File System Master Slave with Elastic File System

[Tim Bain]

I'd guess that the way ActiveMQ is "working" is that your persistent
messages, which should have been stored in the persistence store, are
instead being stored in the memory store.  This means they will not survive
a broker restart/failover even though they should, and you'll be subject to
the memory store's limit rather than the persistence store's.  So yes,
messages are getting delivered, but that doesn't mean ActiveMQ is working.

Could you submit a bug in JIRA to capture the fact that we're not handling
a disk size that large?  I suspect the problem is that we're using an int
where we should be using a long.  Till the bug is fixed, I'd suggest
allocating an EBS volume just for the persistence store that's sized to
match whatever limit you're going to put on the KahaDB store.

Tim

On Aug 25, 2016 2:18 AM, "ishmeister" <ibh...@visibilityltd.com> wrote:

> I'm setting up Active MQ in production with a shared file system
> master/slave
> configuration (KahaDB). I've set everything up and mounted the EFS on both
> EC2 instances.
>
> When I check the disk free stats I get 8 exabytes for the shared file
> system:
>
> $ df -h
> eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0%
> /mnt/efs
> Unfortunately, ActiveMQ cannot interpret this number:
>
> Store limit is 102400 mb (current store usage is 0 mb). The data directory:
> /mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting to
> maximum available disk space: -8796093022207 mb
> Store limit is -8796093022207 mb, whilst the max journal file size for the
> store is: 32 mb, the store will not accept any data when used.
>
> However, this has not prevented ActiveMQ from working as far as I can tell.
> Is it a problem that "the store will not accept any data when used"?
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Active-MQ-Shared-File-System-Master-Slave-with-
> Elastic-File-System-tp4715818.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Active MQ Shared File System Master Slave with Elastic File System

[ishmeister]

I'm setting up Active MQ in production with a shared file system master/slave
configuration (KahaDB). I've set everything up and mounted the EFS on both
EC2 instances.

When I check the disk free stats I get 8 exabytes for the shared file
system:

$ df -h
eu-west-1a.***.efs.eu-west-1.amazonaws.com:/  8.0E 0  8.0E   0% /mnt/efs
Unfortunately, ActiveMQ cannot interpret this number:

Store limit is 102400 mb (current store usage is 0 mb). The data directory:
/mnt/efs/kahadb only has -8796093022208 mb of usable space - resetting to
maximum available disk space: -8796093022207 mb
Store limit is -8796093022207 mb, whilst the max journal file size for the
store is: 32 mb, the store will not accept any data when used.

However, this has not prevented ActiveMQ from working as far as I can tell.
Is it a problem that "the store will not accept any data when used"?



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Shared File System Master/Slave with DRBD

[Greg Eckert]

Hey Mark,

You should be able to use drbd with something like NFS without a 
problem. The LINBIT engineers are in the process publishing an NFS Tech 
guide... For current official documentation, feel free to contact me 
directly.


Best Regards,

Greg

--
: Greg Eckert
: g...@linbit.com
: Not an Engineer
: LINBIT | Your Way to High Availability
: Web: http://www.linbit.com

Re: Shared File System Master/Slave with DRBD

[Mark Anderson]

Greg,

Thanks for the reply. I just wanted to confirm a couple of things.

1) The NFS requirement is so that DRBD can be used in Primary/Primary mode
as the file system needs to be writeable from both nodes?
2) With NFS I would also need to use Pacemaker to make the NFS server HA?
3) Is the NFS Tech Guide listed at
http://www.linbit.com/en/downloads/tech-guides what you are referring to?

Thanks,
Mark


On 1 May 2014 00:34, Greg Eckert g...@linbit.com wrote:

 Hey Mark,

 You should be able to use drbd with something like NFS without a problem.
 The LINBIT engineers are in the process publishing an NFS Tech guide... For
 current official documentation, feel free to contact me directly.

 Best Regards,

 Greg

 --
 : Greg Eckert
 : g...@linbit.com
 : Not an Engineer
 : LINBIT | Your Way to High Availability
 : Web: http://www.linbit.com

Shared File System Master/Slave with DRBD

[Mark Anderson]

Is it possible to use DRBD with shared file system master/slave instead of
a SAN?

Slide 30 at http://www.slideshare.net/ceposta/activemq-59x-new-featuressuggests
this is the case but I haven't been able to find very much
information online.

Before spending time trying it I wanted to check if it was possible and if
there are any known issues. Any pointers to documentation or guides online
would also be appreciated.

Thanks,
Mark

Re: Problem using NFSv4 for Shared File System Master Slave

[Chen]

I created a issue, hope someone can give me a hand, thanks.
https://issues.apache.org/jira/browse/AMQ-4497



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Problem using NFSv4 for Shared File System Master Slave

[Chen]

Hi all,

I'm using ActiveMQ 5.5.1 to be my HA JMS, but recently I've found an
unexpected error.
Both master and slave AMQ can grab the same file lock and receive client's
request one the network back stable from unstable.

In my experiment, I used kahaDB to be the persistenceAdapter.
The setting is like:
persistenceAdapter
　　kahaDB directory=/nfs4/server/data/kahadb/
/persistenceAdapter
There are 2 activeMQs in different machines, and the NFS server is installed
in one of them.
I will use AMQ1 to present the one without out NFS server and AMQ2 for
the other one.

I start AMQ1 earlier then AMQ2, so the AMQ1 grab the file lock and be the
master, AMQ2 be slave brokers and sit in a loop trying to grab the lock from
the master broker.
Then I disconnect AMQ1's network, AMQ2 can grab the file lock and start
working after a while, AMQ1 is still alive and don't show any error message.
After AMQ2 starting working, I enable AMQ1's network, both AMQ1 and AMQ2 can
serve client's request at the same time (I can use webconsole to send
message for both AMQ).
This can cause losing message or restart AMQ failed.

Is this a bug?
I can't find any issue about this, can anyone explain it?
Many thanks.



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SHARED FILE SYSTEM MASTER/SLAVE (newb)

[pico]

configured 2 brokers using the shared file syntax

However, the slave broker is always looking for the database connection and
is not starting up.
Is this the expected behavior?

Log from the slave broker
INFO   | jvm 1| 2013/01/08 10:14:40 |  INFO | Database
\\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
for the database to be unlocked. Reason: java.io.IOException: File
'\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
INFO   | jvm 1| 2013/01/08 10:14:50 |  INFO | Database
\\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
for the database to be unlocked. Reason: java.io.IOException: File
'\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
INFO   | jvm 1| 2013/01/08 10:15:00 |  INFO | Database
\\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
for the database to be unlocked. Reason: java.io.IOException: File
'\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
INFO   | jvm 1| 2013/01/08 10:15:10 |  INFO | Database
\\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
for the database to be unlocked. Reason: java.io.IOException: File
'\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.





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Re: SHARED FILE SYSTEM MASTER/SLAVE (newb)

[Johan Edstrom]

The slave is a standby that will once it can lock the journal reverse the 
roles, so 
the downed node once it is up will start looking for the lock.

On Jan 8, 2013, at 9:38 AM, pico denis.pique...@londonlife.com wrote:

 configured 2 brokers using the shared file syntax
 
 However, the slave broker is always looking for the database connection and
 is not starting up.
 Is this the expected behavior?
 
 Log from the slave broker
 INFO   | jvm 1| 2013/01/08 10:14:40 |  INFO | Database
 \\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
 for the database to be unlocked. Reason: java.io.IOException: File
 '\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
 INFO   | jvm 1| 2013/01/08 10:14:50 |  INFO | Database
 \\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
 for the database to be unlocked. Reason: java.io.IOException: File
 '\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
 INFO   | jvm 1| 2013/01/08 10:15:00 |  INFO | Database
 \\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
 for the database to be unlocked. Reason: java.io.IOException: File
 '\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
 INFO   | jvm 1| 2013/01/08 10:15:10 |  INFO | Database
 \\servername\Shared-Queue\data\kahadb\lock is locked... waiting 10 seconds
 for the database to be unlocked. Reason: java.io.IOException: File
 '\\Ssmsftd1\Shared-Queue\data\kahadb\lock' could not be locked.
 
 
 
 
 
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Shared File System Master Slave locking issues with VM's

[Ryan]

Hi,

I'm currently in the process of setting up a VM image for a Queue server,
the idea is we can use it to scale load. They will share the same File Store
and we have it set up to use the Shared File System Master Slave. So one
should pick up as the master by locking the store and the other comes up as
a slave when it can't lock it.

The problem though is we had some very random results when testing it. We
were writing 2 messages and reading one, making sure the what we got back
was in sequence. Suddenly things went out of whack and when we looked into
it both the Master and Slave seemed to have queues running.

It wasn't until later that i started wondering if it was cause by me saving
the state of the VM. I saved the state of both the Master and Slave. Waited
a while and then started the Slave first. the slave took the lock and became
a Master. Then i resumed the old Master. It still seemed to think that it
was the Master. As far as the Old Master is aware the machine never stopped.  

So can anyone think of a way to help prevent this from happening in terms of
configuring ActiveMQ. We don't want to use Pure Master Slave because it has
no Auto Recovery



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Re: Locking Shared File System Master Slave

[Gary Tully]

For windows, I think you will have to ask the computer.

There is no magic in the code, it is a regular RandomAccessFile channel lock

see: org.apache.kahadb.util.LockFile#lock from:
http://svn.apache.org/viewvc/activemq/trunk/kahadb/src/main/java/org/apache/kahadb/util/LockFile.java?view=markup


On 29 September 2011 23:45,  shaun.t.erick...@accenture.com wrote:
 I'm looking to set up a 'Shared File System Master Slave'. I see that the 
 documentation makes it clear that on Linux, NFSv4 provides proper lock 
 release in the event of the Master's failure.

 What if all my AMQ instances are on Windows 2008 servers? Will a shared 
 Windows directory work? I don't know enough about the Windows filesystem to 
 know if it will also provide the proper locking and lock release needed for 
 this setup.

 What if some of the AMQ servers are on Linux and some are on Windows?

 -ste

 
 This message is for the designated recipient only and may contain privileged, 
 proprietary, or otherwise private information. If you have received it in 
 error, please notify the sender immediately and delete the original. Any 
 other use of the email by you is prohibited.




-- 
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http://blog.garytully.com

Locking Shared File System Master Slave

[shaun.t.erickson]

I'm looking to set up a 'Shared File System Master Slave'. I see that the 
documentation makes it clear that on Linux, NFSv4 provides proper lock release 
in the event of the Master's failure.

What if all my AMQ instances are on Windows 2008 servers? Will a shared Windows 
directory work? I don't know enough about the Windows filesystem to know if it 
will also provide the proper locking and lock release needed for this setup.

What if some of the AMQ servers are on Linux and some are on Windows?

-ste


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proprietary, or otherwise private information. If you have received it in 
error, please notify the sender immediately and delete the original. Any other 
use of the email by you is prohibited.

Support for Shared File System Master Slave using SAMBA/CIFS?

[Magnus]

Hello!

One of our customers runs ActiveMQ on Windows servers and they now wants to
ensure high availability by establish a master slave configuration according
to  http://activemq.apache.org/shared-file-system-master-slave.html
http://activemq.apache.org/shared-file-system-master-slave.html  using a
SAMBA/CIFS share.

But we can't find any info regarding support for SAMBA/CIFS when using this
approach.

Is anyone using the Shared File System Master Slave - configuration using
SAMBA/CIFS?
Is is supported?

Or do we need to switch over to NFS4?
The customer is reluctant to using NFS4 on Windows so this probably means
that we need to switch to Linux bases servers for Active MQ. 

Since changing to Linux means a lot of work we would like to understand our
options before moving on.

Any info in this subject is appreciated!

Regards,
Magnus.





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Re: Support for Shared File System Master Slave using SAMBA/CIFS?

[Dejan Bosanac]

Hi,

I don't have any experience with setting it on cifs, but from little
googling seems like cifs supports file locking which is the only requirement
for this to work. It's best to try it out if you have that environment.


Regards
-- 
Dejan Bosanac - http://twitter.com/dejanb
-
The experts in open source integration and messaging - http://fusesource.com
ActiveMQ in Action - http://www.manning.com/snyder/
Blog - http://www.nighttale.net

Connect at CamelOne http://camelone.com/ May 24-26

The Open Source Integration Conference



On Mon, May 30, 2011 at 2:39 PM, Magnus 
magnus.lars...@callistaenterprise.se wrote:

 Hello!

 One of our customers runs ActiveMQ on Windows servers and they now wants to
 ensure high availability by establish a master slave configuration
 according
 to  http://activemq.apache.org/shared-file-system-master-slave.html
 http://activemq.apache.org/shared-file-system-master-slave.html  using a
 SAMBA/CIFS share.

 But we can't find any info regarding support for SAMBA/CIFS when using this
 approach.

 Is anyone using the Shared File System Master Slave - configuration using
 SAMBA/CIFS?
 Is is supported?

 Or do we need to switch over to NFS4?
 The customer is reluctant to using NFS4 on Windows so this probably means
 that we need to switch to Linux bases servers for Active MQ.

 Since changing to Linux means a lot of work we would like to understand our
 options before moving on.

 Any info in this subject is appreciated!

 Regards,
 Magnus.





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Re: Support for Shared File System Master Slave using SAMBA/CIFS?

[Johan Edstrom]

Cifs / windows file-sharing works fine.
On May 30, 2011, at 9:49 AM, Dejan Bosanac wrote:

 Hi,
 
 I don't have any experience with setting it on cifs, but from little
 googling seems like cifs supports file locking which is the only requirement
 for this to work. It's best to try it out if you have that environment.
 
 
 Regards
 -- 
 Dejan Bosanac - http://twitter.com/dejanb
 -
 The experts in open source integration and messaging - http://fusesource.com
 ActiveMQ in Action - http://www.manning.com/snyder/
 Blog - http://www.nighttale.net
 
 Connect at CamelOne http://camelone.com/ May 24-26
 
 The Open Source Integration Conference
 
 
 
 On Mon, May 30, 2011 at 2:39 PM, Magnus 
 magnus.lars...@callistaenterprise.se wrote:
 
 Hello!
 
 One of our customers runs ActiveMQ on Windows servers and they now wants to
 ensure high availability by establish a master slave configuration
 according
 to  http://activemq.apache.org/shared-file-system-master-slave.html
 http://activemq.apache.org/shared-file-system-master-slave.html  using a
 SAMBA/CIFS share.
 
 But we can't find any info regarding support for SAMBA/CIFS when using this
 approach.
 
 Is anyone using the Shared File System Master Slave - configuration using
 SAMBA/CIFS?
 Is is supported?
 
 Or do we need to switch over to NFS4?
 The customer is reluctant to using NFS4 on Windows so this probably means
 that we need to switch to Linux bases servers for Active MQ.
 
 Since changing to Linux means a lot of work we would like to understand our
 options before moving on.
 
 Any info in this subject is appreciated!
 
 Regards,
 Magnus.
 
 
 
 
 
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 Sent from the ActiveMQ - User mailing list archive at Nabble.com.
 

RE: Feasibility of Shared File System Master Slave using NFSv4

[johneboyer]

Yep, I hired a new Linux consultant and appears to be working like a charm.
Thank you.

FYI: Here’s the output on the slave.

2011-05-26 13:44:09,299 | INFO  | Database /sharedMount/lock is locked...
waiting 10 seconds for the database to be unlocked. Reason:
java.io.IOException: Failed to create directory ‘/sharedMount' |
org.apache.activemq.store.kahadb.MessageDatabase | WrapperSimpleAppMain

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Re: Feasibility of Shared File System Master Slave using NFSv4

[Johan Edstrom]

That looks great!

On May 26, 2011, at 2:52 PM, johneboyer wrote:

 Yep, I hired a new Linux consultant and appears to be working like a charm.
 Thank you.
 
 FYI: Here’s the output on the slave.
 
 2011-05-26 13:44:09,299 | INFO  | Database /sharedMount/lock is locked...
 waiting 10 seconds for the database to be unlocked. Reason:
 java.io.IOException: Failed to create directory ‘/sharedMount' |
 org.apache.activemq.store.kahadb.MessageDatabase | WrapperSimpleAppMain
 
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RE: Feasibility of Shared File System Master Slave using NFSv4

[lexsoto]

It surely works; we are using it with no problems.

Good luck!



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Feasibility of Shared File System Master Slave using NFSv4

[johneboyer]

I’m planning to implement the shared file system master slave using NFSv4 on
Ubuntu (lucid) server. However, my Linux consultant is telling me that it’s
not going to work and has refused to waste time setting it up because he
says the exclusive locking will not work.

Is he correct? Does anyone have experience successfully configuring shared
file system master slave using NFSv4?

Thank you for your time.



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RE: Feasibility of Shared File System Master Slave using NFSv4

[Idzerda, Edan]

I think that's kinda funny, really.  ActiveMQ's website has a warning about 
potential problems with locking under NFSv3,  
http://activemq.apache.org/shared-file-system-master-slave.html and IBM MQ's 
similar multi-instance mode *requires* NFSv4 for proper lock handling. 

I only briefly tested AMQ's master-slave using NFSv3 and it worked well-enough 
in simple test cases.  FWIW, we ended up going with a single server so we could 
use the SAN directly and relied on VmWare for a relatively quick recovery from 
a server failure.


-Original Message-
From: johneboyer [mailto:johnboye...@gmail.com] 
Sent: Thursday, May 19, 2011 2:04 PM
To: users@activemq.apache.org
Subject: Feasibility of Shared File System Master Slave using NFSv4

I’m planning to implement the shared file system master slave using NFSv4 on 
Ubuntu (lucid) server. However, my Linux consultant is telling me that it’s not 
going to work and has refused to waste time setting it up because he says the 
exclusive locking will not work.

Is he correct? Does anyone have experience successfully configuring shared file 
system master slave using NFSv4?

Thank you for your time.



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-
***Note:The information contained in this message may be privileged
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Re: Feasibility of Shared File System Master Slave using NFSv4

[Johan Edstrom]

Sure it does.

http://activemq.apache.org/shared-file-system-master-slave.html


On May 19, 2011, at 12:04 PM, johneboyer wrote:

 I’m planning to implement the shared file system master slave using NFSv4 on
 Ubuntu (lucid) server. However, my Linux consultant is telling me that it’s
 not going to work and has refused to waste time setting it up because he
 says the exclusive locking will not work.
 
 Is he correct? Does anyone have experience successfully configuring shared
 file system master slave using NFSv4?
 
 Thank you for your time.
 
 
 
 --
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Re: Feasibility of Shared File System Master Slave using NFSv4

[johneboyer]

He doesn’t buy it. Unfortunately, I’m not an NFS expert so I feel compelled
to defer to his expertise.

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Re: Feasibility of Shared File System Master Slave using NFSv4

[Johan Edstrom]

Does he honestly think that WIki entry was written as if it just came from the 
mountain and behind a burning bush?

On May 19, 2011, at 1:33 PM, johneboyer wrote:

 He doesn’t buy it. Unfortunately, I’m not an NFS expert so I feel compelled
 to defer to his expertise.
 
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Re: Feasibility of Shared File System Master Slave using NFSv4

[Johan Edstrom]

And here is probably how you want to export it...

rw,wdelay,nohide,insecure,no_root_squash,no_subtree_check,anonuid=65534,anongid=65534

And your slave will say, IOException file bla bal could not be locked.

Once it times out, you failover.



On May 19, 2011, at 1:33 PM, johneboyer wrote:

 He doesn’t buy it. Unfortunately, I’m not an NFS expert so I feel compelled
 to defer to his expertise.
 
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Re: Feasibility of Shared File System Master Slave using NFSv4

[johneboyer]

Thank you for the advise. Sounds like I need to go forward this project with
a willing Linux consultant. 

I’ll post back to the forum with the results.

Regards,
John Boyer

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RE: Feasibility of Shared File System Master Slave using NFSv4

[Allen Reese]

I know that we did some internal testing with NFSv4, and it worked.
Now NFSv3 will not work, it's a matter of when you will get corruption.

--Allen 

 -Original Message-
 From: johneboyer [mailto:johnboye...@gmail.com] 
 Sent: Thursday, May 19, 2011 1:23 PM
 To: users@activemq.apache.org
 Subject: Re: Feasibility of Shared File System Master Slave 
 using NFSv4
 
 Thank you for the advise. Sounds like I need to go forward 
 this project with a willing Linux consultant. 
 
 I'll post back to the forum with the results.
 
 Regards,
 John Boyer
 
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 Sent from the ActiveMQ - User mailing list archive at Nabble.com.
 

Re: Which Persistence Adapter to Use for Shared File System Master/Slave

[Dejan Bosanac]

Hi,

for shared filesystem master slave setup you should use either KahaDB (from
5.3.0 on) or ActiveMQ persistence adapter (on earlier versions). If you plan
to have shared database master slave, that you should use JDBC persistence
adapter (without journaling).

Cheers
--
Dejan Bosanac - http://twitter.com/dejanb

Open Source Integration - http://fusesource.com/
ActiveMQ in Action - http://www.manning.com/snyder/
Blog - http://www.nighttale.net


On Mon, Apr 5, 2010 at 9:36 AM, Feng AtWork feng8w...@gmail.com wrote:

 Hi, There,

 I have been evaluating ActiveMQ for our new project for the past few weeks,
 and I cannot find a conclusive answer about exactly which persistence
 adapters can be used with a shared file system master/slave set up.

 There seems to be some conflicting information out there, for example:

 1) according to Bruce Snyder in this thread,

 http://markmail.org/message/ldjoyewy3jczcaai?q=shared+file+system++list:org.apache.activemq.users
 ,
 it seems journaledJBDC can only be used with shared JDBC master/slave,

 but 2) the example in
 http://activemq.apache.org/shared-file-system-master-slave.html shows to
 use
 just the journaledJDBC adapter with shared file system master/slave;

 and 3), according to the same thread in 1), AMQ persistence should be used
 with shared file system master/slave.

 And what about  kahaPersistenceAdapter, it is file based, but the above
 thread mentions http://activemq.apache.org/kahadb-master-slave.html, which
 uses zookeeper and is not supported.

 Finally, what is the different between kahaPersistenceAdapter in
 kahaPersistenceAdapter dir=target/kaha-data/ and just kaha in kahaDB
 directory=activemq-data journalMaxFileLength=32mb/.   Are
 kahaPersistenceAdater and kahaDB the same thing?   If
 kahaPersistenceAdapter
 cannot be used with shared file system JDBC, can kahaDB be used instead?

 Any clarification will be much appreciated.  We load tested journaledJDBC
 with default derby data source and an Oracle data source, the performance
 were not satisfactory.

 Thanks.

 -Feng

Re: Which Persistence Adapter to Use for Shared File System Master/Slave

[Feng AtWork]

Thanks.  Figured that out as well from the early draft of ActiveMQ in Action
book.

-Feng

On Tue, Apr 6, 2010 at 1:52 AM, Dejan Bosanac de...@nighttale.net wrote:

 Hi,

 for shared filesystem master slave setup you should use either KahaDB (from
 5.3.0 on) or ActiveMQ persistence adapter (on earlier versions). If you
 plan
 to have shared database master slave, that you should use JDBC persistence
 adapter (without journaling).

 Cheers
 --
 Dejan Bosanac - http://twitter.com/dejanb

 Open Source Integration - http://fusesource.com/
 ActiveMQ in Action - http://www.manning.com/snyder/
 Blog - http://www.nighttale.net


 On Mon, Apr 5, 2010 at 9:36 AM, Feng AtWork feng8w...@gmail.com wrote:

  Hi, There,
 
  I have been evaluating ActiveMQ for our new project for the past few
 weeks,
  and I cannot find a conclusive answer about exactly which persistence
  adapters can be used with a shared file system master/slave set up.
 
  There seems to be some conflicting information out there, for example:
 
  1) according to Bruce Snyder in this thread,
 
 
 http://markmail.org/message/ldjoyewy3jczcaai?q=shared+file+system++list:org.apache.activemq.users
  ,
  it seems journaledJBDC can only be used with shared JDBC master/slave,
 
  but 2) the example in
  http://activemq.apache.org/shared-file-system-master-slave.html shows to
  use
  just the journaledJDBC adapter with shared file system master/slave;
 
  and 3), according to the same thread in 1), AMQ persistence should be
 used
  with shared file system master/slave.
 
  And what about  kahaPersistenceAdapter, it is file based, but the above
  thread mentions http://activemq.apache.org/kahadb-master-slave.html,
 which
  uses zookeeper and is not supported.
 
  Finally, what is the different between kahaPersistenceAdapter in
  kahaPersistenceAdapter dir=target/kaha-data/ and just kaha in kahaDB
  directory=activemq-data journalMaxFileLength=32mb/.   Are
  kahaPersistenceAdater and kahaDB the same thing?   If
  kahaPersistenceAdapter
  cannot be used with shared file system JDBC, can kahaDB be used instead?
 
  Any clarification will be much appreciated.  We load tested journaledJDBC
  with default derby data source and an Oracle data source, the performance
  were not satisfactory.
 
  Thanks.
 
  -Feng
 

Which Persistence Adapter to Use for Shared File System Master/Slave

[Feng AtWork]

Hi, There,

I have been evaluating ActiveMQ for our new project for the past few weeks,
and I cannot find a conclusive answer about exactly which persistence
adapters can be used with a shared file system master/slave set up.

There seems to be some conflicting information out there, for example:

1) according to Bruce Snyder in this thread,
http://markmail.org/message/ldjoyewy3jczcaai?q=shared+file+system++list:org.apache.activemq.users,
it seems journaledJBDC can only be used with shared JDBC master/slave,

but 2) the example in
http://activemq.apache.org/shared-file-system-master-slave.html shows to use
just the journaledJDBC adapter with shared file system master/slave;

and 3), according to the same thread in 1), AMQ persistence should be used
with shared file system master/slave.

And what about  kahaPersistenceAdapter, it is file based, but the above
thread mentions http://activemq.apache.org/kahadb-master-slave.html, which
uses zookeeper and is not supported.

Finally, what is the different between kahaPersistenceAdapter in
kahaPersistenceAdapter dir=target/kaha-data/ and just kaha in kahaDB
directory=activemq-data journalMaxFileLength=32mb/.   Are
kahaPersistenceAdater and kahaDB the same thing?   If kahaPersistenceAdapter
cannot be used with shared file system JDBC, can kahaDB be used instead?

Any clarification will be much appreciated.  We load tested journaledJDBC
with default derby data source and an Oracle data source, the performance
were not satisfactory.

Thanks.

-Feng

Options for Shared File System Master Slave

[janylj]

Hello,

I am researching on the options for Shared File System Master Slave and
found this comment earlier:
You really have three choices:  NAS:  CIFS or NFS; SAN:  GFS (cluster file
system)

I don't have much knowledge on NAS or SAN. Would you please recommend some
products for these technologies, preferably open source ones? 

Also I played with Hadoop distributed file system. However, I don't think
Hadoop works in this case. I could not find a specific shared file system
directory which could be configured into activemq. But isn't Hadoop a GFS?
If anyone has considered Hadoop, please advise whether it's applicable.

Thank you very much.

Lijun
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Re: Shared File System Master Slave Tips?

[Mario Siegenthaler]

We've tried it on NFS on linux and it didn't work (some locking issue
with java and nfs). However it worked with windows shares, but we're
not using it because we run linux boxes.

Mario

On 5/31/07, Michael Slattery [EMAIL PROTECTED] wrote:

Hello List!

I'm interested in putting together the Shared File System Master
Slave scenario in a managed hosting setup.   What are you using to
achieve the shared file system master slave on your installs?

I would appreciate it very much if folks on this list would share
descriptions of successful environments. SAN/NAS, Filesystems,
etc would be very helpful.

If you are doing this in a managed hosting environment, even
better!It's not easy to determine who is doing SAN with shared
access or decent NAS from the vendor websites out there (rackspace
and the like).

Last case, if you tried Shared File System Master Slave but found
that you had to go with JDBC that would also be helpful.

Thank you.
Mike

Shared File System Master Slave Tips?

[Michael Slattery]

Hello List!

I'm interested in putting together the Shared File System Master  
Slave scenario in a managed hosting setup.   What are you using to  
achieve the shared file system master slave on your installs?


I would appreciate it very much if folks on this list would share  
descriptions of successful environments. SAN/NAS, Filesystems,  
etc would be very helpful.


If you are doing this in a managed hosting environment, even  
better!It's not easy to determine who is doing SAN with shared  
access or decent NAS from the vendor websites out there (rackspace  
and the like).


Last case, if you tried Shared File System Master Slave but found  
that you had to go with JDBC that would also be helpful.


Thank you.
Mike

Re: Shared File System Master Slave with OCFS

[James Strachan]

On 5/19/07, Christopher G. Stach II [EMAIL PROTECTED] wrote:

James Strachan wrote:

 Thanks for the heads up! :)

 I guess we could make the locking strategy pluggable  we could have
 some implementation call the fcntl locking. e.g. maybe using Jtux

 http://www.basepath.com/aup/jtux/


Even though one could achieve this, I don't know what the benefit would
be.


Allow folks to run multiple broker instances on a shared file system
so that if one broker fails, another takes over.
http://activemq.apache.org/shared-file-system-master-slave.html



  It only shifts the responsibility down.  At least the user would
want a broker that is dependent on one or more brokers.  Each of those
brokers shouldn't be dependent on each other for locking, data, or
anything else.  I can appreciate that some people assume that shared
data is available, but shared data is just as easily corrupted, locked,
or unavailable.  Essentially, when you find a single responsibility and
divide it, it probably shouldn't converge somewhere down the line.  This
current pattern is most likely unusable for any HA situation.


Agreed - I'd much prefer a share nothing HA strategy where folks can
spin up and down brokers at any point in time and everything just
works (tm) with messages replicated onto multiple physical stores and
things auto-partitioning etc.

However we're not there yet, so its a question of trade-offs. Some
folks find it easier to rely on their shared file system / SAN to do
the HA; others can use the share-nothing approach in ActiveMQ (Pure
Master Slave)...
http://activemq.apache.org/masterslave.html

and live with the current limitations (no automatic fail-back of the
old master when it is brought back online).

Like many things in IT its a tradeoff. For now, today, the shared file
system approach is a pretty reasonable approach; if you already have a
reliable distributed file system (particularly if you have a SAN).

--
James
---
http://macstrac.blogspot.com/

Re: Shared File System Master Slave with OCFS

[Christopher G. Stach II]

James Strachan wrote:
 
 Thanks for the heads up! :)
 
 I guess we could make the locking strategy pluggable  we could have
 some implementation call the fcntl locking. e.g. maybe using Jtux
 
 http://www.basepath.com/aup/jtux/
 

Even though one could achieve this, I don't know what the benefit would
be.  It only shifts the responsibility down.  At least the user would
want a broker that is dependent on one or more brokers.  Each of those
brokers shouldn't be dependent on each other for locking, data, or
anything else.  I can appreciate that some people assume that shared
data is available, but shared data is just as easily corrupted, locked,
or unavailable.  Essentially, when you find a single responsibility and
divide it, it probably shouldn't converge somewhere down the line.  This
current pattern is most likely unusable for any HA situation.

-- 
Christopher G. Stach II

Re: Shared File System Master Slave with OCFS

[Christopher G. Stach II]

Christopher G. Stach II wrote:
 James Strachan wrote:
 Thanks for the heads up! :)

 I guess we could make the locking strategy pluggable  we could have
 some implementation call the fcntl locking. e.g. maybe using Jtux

 http://www.basepath.com/aup/jtux/

 
 Even though one could achieve this, I don't know what the benefit would
 be.  It only shifts the responsibility down.  At least the user would
 want a broker that is dependent on one or more brokers.  Each of those
 brokers shouldn't be dependent on each other for locking, data, or
 anything else.  I can appreciate that some people assume that shared
 data is available, but shared data is just as easily corrupted, locked,
 or unavailable.  Essentially, when you find a single responsibility and
 divide it, it probably shouldn't converge somewhere down the line.  This
 current pattern is most likely unusable for any HA situation.
 

Wow.  That sounded kind of snotty. :)  I meant client that is
dependent, too.

-- 
Christopher G. Stach II

Re: Shared File System Master Slave with OCFS

[James Strachan]

On 5/18/07, James Strachan [EMAIL PROTECTED] wrote:

On 5/17/07, felipera [EMAIL PROTECTED] wrote:
 Hi everyone,

 I am trying to setup two MQ Servers (4.1.1), sharing the same data directory
 (I tried Derby and Kaha), on top of OCFS, but the locking doesn't seem to be
 working. It works fine when both MQs are running on the same server (still
 using OCFS). I see the second MQ waiting for the lock to be released
 (Journal is locked... waiting 10 seconds for the journal to be unlocked.).
 That's why I am not sure if it's a OCFS issue. But when I run each MQ in
 separate boxes (still sharing the same data directory using OCFS) it doesn't
 work, they both start successfully.

This is the OCFS you're talking about right?
http://en.wikipedia.org/wiki/OCFS2


Actually OCFS2 seems more like a real distributed file system for
general purpose use; the OCFS looks more specifically for using to
host oracle data tables. Am wondering how good the file locking is on
OCFS? Certainly its clear the mutex file locking from Java isn't
supported on OCFS.

--
James
---
http://macstrac.blogspot.com/

Re: Shared File System Master Slave with OCFS

[James Strachan]

On 5/17/07, felipera [EMAIL PROTECTED] wrote:

Hi everyone,

I am trying to setup two MQ Servers (4.1.1), sharing the same data directory
(I tried Derby and Kaha), on top of OCFS, but the locking doesn't seem to be
working. It works fine when both MQs are running on the same server (still
using OCFS). I see the second MQ waiting for the lock to be released
(Journal is locked... waiting 10 seconds for the journal to be unlocked.).
That's why I am not sure if it's a OCFS issue. But when I run each MQ in
separate boxes (still sharing the same data directory using OCFS) it doesn't
work, they both start successfully.


This is the OCFS you're talking about right?
http://en.wikipedia.org/wiki/OCFS2

I guess the file locking isn't working from Java. I wonder how to use
file locking properly on OCFS.


I am thinking about using a network of brokers, since I don't know what else
to try.


If you want clustering  replicated message stores you could try one
of the other Master/Slave implementations.
http://activemq.apache.org/masterslave.html

FWIW Networks of Brokers is for store and forward of messages only;
messages are never replicated in multiple locations with networks of
brokers.

--
James
---
http://macstrac.blogspot.com/

Re: Shared File System Master Slave with OCFS

[Christopher G. Stach II]

James Strachan wrote:
 On 5/18/07, James Strachan [EMAIL PROTECTED] wrote:
 On 5/17/07, felipera [EMAIL PROTECTED] wrote:
  Hi everyone,
 
  I am trying to setup two MQ Servers (4.1.1), sharing the same data
 directory
  (I tried Derby and Kaha), on top of OCFS, but the locking doesn't
 seem to be
  working. It works fine when both MQs are running on the same server
 (still
  using OCFS). I see the second MQ waiting for the lock to be released
  (Journal is locked... waiting 10 seconds for the journal to be
 unlocked.).
  That's why I am not sure if it's a OCFS issue. But when I run each
 MQ in
  separate boxes (still sharing the same data directory using OCFS) it
 doesn't
  work, they both start successfully.

 This is the OCFS you're talking about right?
 http://en.wikipedia.org/wiki/OCFS2
 
 Actually OCFS2 seems more like a real distributed file system for
 general purpose use; the OCFS looks more specifically for using to
 host oracle data tables. Am wondering how good the file locking is on
 OCFS? Certainly its clear the mutex file locking from Java isn't
 supported on OCFS.
 

OCFS2 properly supports POSIX locking semantics with fcntl.  lockf and
flock aren't supported yet.  If that's what the JVM uses under the
covers, you're out of luck.  If this is about OCFS and not OCFS2, I'm
really sorry. :)

-- 
Christopher G. Stach II

Re: Shared File System Master Slave with OCFS

[James Strachan]

On 5/18/07, Christopher G. Stach II [EMAIL PROTECTED] wrote:

James Strachan wrote:
 On 5/18/07, James Strachan [EMAIL PROTECTED] wrote:
 On 5/17/07, felipera [EMAIL PROTECTED] wrote:
  Hi everyone,
 
  I am trying to setup two MQ Servers (4.1.1), sharing the same data
 directory
  (I tried Derby and Kaha), on top of OCFS, but the locking doesn't
 seem to be
  working. It works fine when both MQs are running on the same server
 (still
  using OCFS). I see the second MQ waiting for the lock to be released
  (Journal is locked... waiting 10 seconds for the journal to be
 unlocked.).
  That's why I am not sure if it's a OCFS issue. But when I run each
 MQ in
  separate boxes (still sharing the same data directory using OCFS) it
 doesn't
  work, they both start successfully.

 This is the OCFS you're talking about right?
 http://en.wikipedia.org/wiki/OCFS2

 Actually OCFS2 seems more like a real distributed file system for
 general purpose use; the OCFS looks more specifically for using to
 host oracle data tables. Am wondering how good the file locking is on
 OCFS? Certainly its clear the mutex file locking from Java isn't
 supported on OCFS.


OCFS2 properly supports POSIX locking semantics with fcntl.  lockf and
flock aren't supported yet.  If that's what the JVM uses under the
covers, you're out of luck.  If this is about OCFS and not OCFS2, I'm
really sorry. :)


Thanks for the heads up! :)

I guess we could make the locking strategy pluggable  we could have
some implementation call the fcntl locking. e.g. maybe using Jtux

http://www.basepath.com/aup/jtux/



--
James
---
http://macstrac.blogspot.com/

Shared File System Master Slave with OCFS

[felipera]

Hi everyone,

I am trying to setup two MQ Servers (4.1.1), sharing the same data directory
(I tried Derby and Kaha), on top of OCFS, but the locking doesn't seem to be
working. It works fine when both MQs are running on the same server (still
using OCFS). I see the second MQ waiting for the lock to be released
(Journal is locked... waiting 10 seconds for the journal to be unlocked.).
That's why I am not sure if it's a OCFS issue. But when I run each MQ in
separate boxes (still sharing the same data directory using OCFS) it doesn't
work, they both start successfully.

I tried using jdbc:
journaledJDBC journalLogFiles=5 useDatabaseLock=true
dataDirectory=${activemq.base}/activemq-data/

And Kaha:
kahaPersistenceAdapter dir=${activemq.base}/activemq-data
maxDataFileLength=33554432/

I am thinking about using a network of brokers, since I don't know what else
to try. I tried with ActiveMQ 4.2 without luck either.

Could you someone help me please?

Thank you in advance,
Felipe
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Shared File System Master/Slave Problem

[TheKK]

: 

org.apache.activemq.transport.InactivityMonitor$1
at 

edu.emory.mathcs.backport.java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.compareTo(ScheduledThreadPoolE

xecutor.java:189)
at
edu.emory.mathcs.backport.java.util.PriorityQueue.remove(PriorityQueue.java:507)
at
edu.emory.mathcs.backport.java.util.concurrent.DelayQueue.remove(DelayQueue.java:379)
at 

edu.emory.mathcs.backport.java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.remove(ScheduledThreadPoolExecuto

r.java:707)
at
edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.remove(ThreadPoolExecutor.java:1582)
at org.apache.activemq.thread.Scheduler.cancel(Scheduler.java:55)
at
org.apache.activemq.transport.InactivityMonitor.stopMonitorThreads(InactivityMonitor.java:176)
at
org.apache.activemq.transport.InactivityMonitor.onException(InactivityMonitor.java:149)
at
org.apache.activemq.transport.TransportSupport.onException(TransportSupport.java:97)
at
org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:150)
at java.lang.Thread.run(Thread.java:595)
Shutting down


Receiver Application Log:
=
Got Message: [File1 - Message1File1 - Message2File1 - Message3File1 -
Message4]
Got Message: [File10 - Message1File10 - Message2File10 - Message3File10 -
Message4]
Got Message: [File11 - Message1File11 - Message2File11 - Message3File11 -
Message4]
Got Message: [File12 - Message1File12 - Message2File12 - Message3File12 -
Message4]
Got Message: [File13 - Message1File13 - Message2File13 - Message3File13 -
Message4]
Got Message: [File14 - Message1File14 - Message2File14 - Message3File14 -
Message4]
Got Message: [File15 - Message1File15 - Message2File15 - Message3File15 -
Message4]
Got Message: [File16 - Message1File16 - Message2File16 - Message3File16 -
Message4]
Got Message: [File 17 - Message1File 17 - Message2File 17 - Message3File 17
- Message4]
Got Message: [File18 - Message1File18 - Message2File18 - Message3File18 -
Message4]
Got Message: [File2 - Message1File2 - Message2File2 - Message3File2 -
Message4]
Exception in thread ActiveMQ Transport: tcp://localhost/127.0.0.1:61616
java.lang.ClassCastException: 

org.apache.activemq.transport.InactivityMonitor$1
at 

edu.emory.mathcs.backport.java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.compareTo(ScheduledThreadPoolE

xecutor.java:189)
at
edu.emory.mathcs.backport.java.util.PriorityQueue.remove(PriorityQueue.java:507)
at
edu.emory.mathcs.backport.java.util.concurrent.DelayQueue.remove(DelayQueue.java:379)
at 

edu.emory.mathcs.backport.java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.remove(ScheduledThreadPoolExecuto

r.java:707)
at
edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.remove(ThreadPoolExecutor.java:1582)
at org.apache.activemq.thread.Scheduler.cancel(Scheduler.java:55)
at
org.apache.activemq.transport.InactivityMonitor.stopMonitorThreads(InactivityMonitor.java:176)
at
org.apache.activemq.transport.InactivityMonitor.onException(InactivityMonitor.java:149)
at
org.apache.activemq.transport.TransportSupport.onException(TransportSupport.java:97)
at
org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:150)
at java.lang.Thread.run(Thread.java:595)




Summary:
=

Version : apache-activemq-4.2-SNAPSHOT

Sender is able to reconnect the with Broker B and continues publishing
messages to destination testTopic. 
The receiver is not able to reconnect like the sender and not able to
receive any messages.
Please let me know if there is any configuration/property needs to set for
the receiver to reconnect.

Also pls let me know the steps for configuring JBDC Master/Slave.

Thanks in advance,
KK

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Re: Re: Shared File System Master Slave with Windows

[Dingwen Yuan]

I have tried the latest version - apache-activemq-4.2-20070328.130210-35, but 
the same error still exists. With what are you going to substitute activeio?

Thank you!




Dingwen Yuan
2007-04-10



发件人： James Strachan
发送时间： 2007-04-03 15:49:52
收件人： users@activemq.apache.org
抄送： 
主题： Re: Shared File System Master Slave with Windows

On 4/3/07, pdvyuan  [EMAIL PROTECTED]  wrote:
 Hi all,

 Can I use a shared windows file system to achieve Shared File System Master 
 Slave? I have made some tests, but occasionally some error would occur. I 
 made the test under 2 instances of activemq-4.2 runing on WinXP. The errors 
 are as follows:

 2007-03-30 17:04:33,640 [28.64.7.49:4858] DEBUG JournalMessageStore   
  - Journalled message add for: 
 ID:xuj01-a7d120-3614-1174637145906-0:0:1:1:296058, at: 39:3829174
 2007-03-30 17:04:33,687 [eckpoint Worker] DEBUG JournalPersistenceAdapter 
  - Checkpoint started.
 2007-03-30 17:04:33,703 [8.64.7.111:1333] DEBUG JournalMessageStore   
  - Journalled message remove for: 
 ID:xuj01-a7d120-3615-1174637145921-1:0:1:1:109282, at: 39:3830090
 2007-03-30 17:04:33,781 [eckpoint Worker] DEBUG JournalPersistenceAdapter 
  - Marking journal at: 39:3829174
 2007-03-30 17:04:33,781 [eckpoint Worker] ERROR JournalPersistenceAdapter 
  - Failed to mark the Journal: 
 org.apache.activeio.journal.InvalidRecordLocationException: The location is 
 less than the last mark.
 org.apache.activeio.journal.InvalidRecordLocationException: The location is 
 less than the last mark.
  at 
 org.apache.activeio.journal.active.JournalImpl.setMark(JournalImpl.java:340)
  at 
 org.apache.activemq.store.journal.JournalPersistenceAdapter.doCheckpoint(JournalPersistenceAdapter.java:400)
  at 
 org.apache.activemq.store.journal.JournalPersistenceAdapter$2.iterate(JournalPersistenceAdapter.java:128)
  at 
 org.apache.activemq.thread.DedicatedTaskRunner.runTask(DedicatedTaskRunner.java:88)
  at 
 org.apache.activemq.thread.DedicatedTaskRunner.access$000(DedicatedTaskRunner.java:25)
  at 
 org.apache.activemq.thread.DedicatedTaskRunner$1.run(DedicatedTaskRunner.java:39)
 2007-03-30 17:04:33,781 [eckpoint Worker] DEBUG JournalPersistenceAdapter 
  - Checkpoint done.

 Is this error due to the insufficient support of exclusive file locks by 
 Windows.

The above looks like a bug. I'm guessing you've used a fairly old
snapshot of 4.2, I'd recommend using a recent one from the end of
March 2007 which no longer uses activeio AFAIK.

http://people.apache.org/repo/m2-snapshot-repository/org/apache/activemq/apache-activemq/4.2-SNAPSHOT/

-- 

James
---
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