Thanks for you reply, The main reason why I don't use NFS is that I need to
ensure the high availability of the NFS cluster or rely on third-party storage,
which will increase my cost.
The leveldb + zookeeper mode, when building a cluster, can ensure that each
node can store a piece of data, so I do not need to rely on third-party
storage. and I don't need to worry about the stability of the third-party
storage??
Based on the above considerations, will the community add similar functions in
activemq5. X version
------------------ ???????? ------------------
??????:
"users"
<tb...@alumni.duke.edu>;
????????: 2021??7??8??(??????) ????7:50
??????: "ActiveMQ Users"<users@activemq.apache.org>;
????: Re: I have a question about levedb
Thanks for the link. To the best of my knowledge, that particular
experiment never bore fruit and there is no current effort underway to
implement replicated KahaDB.
Regarding NFS, I agree, I wouldn't run a single NFS server for exactly that
reason. Running your own NFS cluster in clustered mode would be one option
to ensure resiliency. Running a single NFS process in front of a storage
array would be another, but you'd still have availability concerns even
though you've resolved the durability concerns. Another would be a managed
offering such as AWS EFS, which takes all the work off your plate. (I'd use
EFS if it were me.) But yes, a single NFS server writing to local storage
is not what I had in mind, for exactly the reasons you identified, but that
doesn't mean that NFS as a whole isn't a viable option.
Also note that if your organization already has a resilient NFS service,
you could host your data there rather than build your own just to hold
these KahaDB files.
Tim
On Thu, Jul 8, 2021, 12:08 AM ??????o.-- <1169114...@qq.com.invalid> wrote:
> Hello, you may have misunderstood me. First ,??Can you please provide the
> link where you saw KahaDB replication discussed???This is the website[1]
> Second:
> "In the KahaDB on NFS case, your statement that the data is unavailable
> when
> a broker fails is inaccurate. Because the data is written to an NFS share,
> it is readable by many machines, and as soon as a new broker can acquire
> the lock due to the active broker's failure, the machine that acquires the
> lock will become the active broker"
> I know what you mean ,when a broker fails ,a new broker can become a
> master.
> but wWhat worries me is that after the server where the NFS storage is
> located goes down, the whole cluster will be paralyzed,
>
>
>
>
>
>
>
>
> 1.https://activemq.apache.org/kahadb-replication-experimental
>
>
>
>
>
>
> ------------------&nbsp;????????&nbsp;------------------
> ??????:
>
"users"
>
<
> tb...@alumni.duke.edu&gt;;
> ????????:&nbsp;2021??7??7??(??????) ????8:08
> ??????:&nbsp;"ActiveMQ Users"<users@activemq.apache.org&gt;;
>
> ????:&nbsp;Re: I have a question about levedb
>
>
>
> Can you please provide the link where you saw KahaDB replication discussed?
> I suspect that the content is very out of date since I'm not aware of any
> current development effort to implement replicated KahaDB.
>
> To the best of my knowledge, the out-of-the-box data store options
> available to you are KahaDB on NFS and JDBC (with a number of database
> engines supported). You can also use pluggable storage lockers[1] to
> decouple the locking technology from the storage technology if necessary
> (e.g. for NFSv3 whose locks are not supported).
>
> In the KahaDB on NFS case, your statement that the data is unavailable when
> a broker fails is inaccurate. Because the data is written to an NFS share,
> it is readable by many machines, and as soon as a new broker can acquire
> the lock due to the active broker's failure, the machine that acquires the
> lock will become the active broker, read the data file, and begin receiving
> and delivering messages from/to clients. So I think your assessment that
> replicated LevelDB is necessary to get resilience without having to use a
> SQL database wasn't accurate and led you down the wrong path. You should
> use KahaDB on NFSv4.
>
> 1. https://activemq.apache.org/pluggable-storage-lockers
>
> Tim
>
> On Wed, Jul 7, 2021, 12:13 AM ??????o.-- <1169114...@qq.com.invalid&gt;
> wrote:
>
> &gt; I learned from the official website that the master-slave modes
> currently
> &gt; supported are "shared file system master slave" and "JDBC master
> slave".
> &gt;
> &gt;
> &gt; "Shared file system master slave": the mode depends on shared
files
> and
> &gt; only exists on one node. If the host of the node is down, the
> master-slave
> &gt; mode will be invalid
> &gt;
> &gt;
> &gt; "JDBC": the mode needs to rely on the database, which costs a
lot. At
> the
> &gt; same time, the database needs to have the master / slave mode, so
> that the
> &gt; cluster can be robust.
> &gt;
> &gt;
> &gt; So I had to use activemq+zookeeeper to avoid shared file storage
and
> JDBC
> &gt; database storage
> &gt;
> &gt; We learned from the official website that masterslave
&amp;gt; kahadb
> &gt; replication (experimental) is in the experimental stage. Is this
mode
> &gt; similar to the previous ActiveMQ + zookeeper + leveldb and
> independent of
> &gt; shared files?At the same time, when can we go online to provide
> services
> &gt;
> &gt;
> &gt;
------------------&amp;nbsp;????????&amp;nbsp;------------------
> &gt; ??????:
>
&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
> "users"
>
&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
> <
> &gt; tb...@alumni.duke.edu&amp;gt;;
> &gt; ????????:&amp;nbsp;2021??7??5??(??????) ????7:40
> &gt; ??????:&amp;nbsp;"ActiveMQ
Users"<users@activemq.apache.org&amp;gt;;
> &gt;
> &gt; ????:&amp;nbsp;Re: I have a question about levedb
> &gt;
> &gt;
> &gt;
> &gt; Let me strengthen the statement made by Justin.
> &gt;
> &gt; The decision to deprecate and soon remove LevelDB was made because
> there
> &gt; was no developer willing/able to maintain the code and no member
of
> the
> &gt; mailing list willing/able to answer questions, even basic ones, on
> this
> &gt; mailing list.
> &gt;
> &gt; If you aren't prepared to answer your own questions by reading the
> source
> &gt; code without any support from this mailing list, and to debug and
fix
> any
> &gt; bugs you encounter in the Scala code, don't use LevelDB.
> &gt;
> &gt; And even if you're willing to do those things, you'll be unable to
> upgrade
> &gt; ActiveMQ to 5.17.0 or later, even if there are security
> vulnerabilities or
> &gt; other compelling reasons to upgrade. I strongly encourage you to
> switch to
> &gt; KahaDB immediately.
> &gt;
> &gt; Tim
> &gt;
> &gt; On Sun, Jul 4, 2021, 11:45 PM ??????o.--
<1169114...@qq.com.invalid
> &amp;gt;
> &gt; wrote:
> &gt;
> &gt; &amp;gt; I know the levedb was removed.
> &gt; &amp;gt; but now I use zookeeper + ActiveMQ to build
master-slave
> mode??
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt;
>
------------------&amp;amp;nbsp;????????&amp;amp;nbsp;------------------
> &gt; &amp;gt; ??????:
> &gt;
>
&amp;gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;
> &gt; "users"
> &gt;
>
&amp;gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;
> &gt; <
> &gt; &amp;gt; jbert...@apache.org&amp;amp;gt;;
> &gt; &amp;gt; ????????:&amp;amp;nbsp;2021??7??5??(??????)
????11:22
> &gt; &amp;gt;
??????:&amp;amp;nbsp;"users"<users@activemq.apache.org
> &amp;amp;gt;;
> &gt; &amp;gt;
> &gt; &amp;gt; ????:&amp;amp;nbsp;Re: I have a question about
levedb
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt; Support for LevelDB was revoked in ActiveMQ 5.14.2,
although
> the store
> &gt; &amp;gt; implementation was still present in the code-base.
The store
> &gt; implementation
> &gt; &amp;gt; was removed in 5.17.0.
> &gt; &amp;gt;
> &gt; &amp;gt;
> &gt; &amp;gt; Justin
> &gt; &amp;gt;
> &gt; &amp;gt; On Sun, Jul 4, 2021 at 9:48 PM ??????o.--
> <1169114...@qq.com.invalid
> &gt; &amp;amp;gt;
> &gt; &amp;gt; wrote:
> &gt; &amp;gt;
> &gt; &amp;gt; &amp;amp;gt; Hi&amp;amp;amp;nbsp;
> &gt; &amp;gt; &amp;amp;gt;
> &gt; &amp;gt; &amp;amp;gt;
> &gt; &amp;gt;
> &gt;
>
https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120
> &gt
>
<https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120&gt>;
> &amp;gt
> &gt; <
>
https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120&amp;gt&gt
> ;;
> &gt; &amp;amp;gt
> &gt; &amp;gt; <
> &gt;
>
https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120&amp;amp;gt&amp;gt
> &gt
>
<https://github.com/apache/activemq/blob/activemq-5.15.x/activemq-leveldb-store/src/main/scala/org/apache/activemq/leveldb/replicated/MasterElector.scala#L120&amp;amp;gt&amp;gt&gt>;
> ;;
> &gt; &amp;gt; what is means "members"??
> &gt; &amp;gt; &amp;amp;gt; Refers to the number of brokers
started in the
> current
> &gt; cluster, or the
> &gt; &amp;gt; &amp;amp;gt; number of brokers registered in the
zookeeper
> service
