Re: Data sync between 2 clusters in single DC

[suraj pasuparthy]

Yes, should be possible .. u will need to set ur keyspaces accordingly to
create replicas on each cass cluster ..

Thanks
Suraj

On Mon, Oct 30, 2017 at 1:11 PM Rahul Neelakantan <ra...@rahul.be> wrote:

> Why wouldnt you set it up as a single cluster that spans 2 DCs?
>
> On Mon, Oct 30, 2017 at 4:09 PM, Vincent Lee <vlee...@gmail.com> wrote:
>
>> For high availability in a single DC region, I would like to install one
>> Cassandra cluster on one AZ and a second cluster on a different AZ.
>> The data between them needs to be synchronized. Is this possible?
>>
>> Note that this is for a single DC (region).
>> Currently I am using GossipingPropertyFileSnitch.
>>
>> I look forward for your input.
>>
>
> --
Suraj Pasuparthy

Re: Guaranteed order for syncing Records

[suraj pasuparthy]

thanks Pranay,
But is the order maintained across tables?
As in the client in DC1 first writes record A in table A and then
immediately writes Record B in Table B,
So will the order be maintained, where in Table A gets synced first and
then Table B?

Thanks again
-Suraj

On Wed, Jul 5, 2017 at 11:08 PM, Pranay akula <pranay.akula2...@gmail.com>
wrote:

> Hello suraj,
>
> Nope there will no out sync between same tables in different Datacenters,
> so Record A in Table A in Datacenter 1 will also be in Table A in
> Datacenter 2, just make sure there is no communication issues between
> Datacenters.
>
>
> Thanks
> Pranay.
>
> On Thu, Jul 6, 2017 at 2:01 AM, suraj pasuparthy <
> suraj.pasupar...@gmail.com> wrote:
>
>> Hello Experts,
>> I had a question
>>
>> We have a multi DC cluster for cassandra and wanted to confirm one
>> behavior.
>> Are the records order maintained while syncing to the backup datacenter?
>> What i mean is, if say, Record A is written to a Table A and Record B is
>> written to Table B on Datacenter 1, Does cassandra ensure that first Record
>> A is synced to Table A in Datacenter 2 and then the Record B syncs to table
>> B ?
>>
>> Is there a possibility of "out of order " syncs between datacenters ?
>>
>> --
>> Suraj Pasuparthy
>>
>>
>


-- 
Suraj Pasuparthy

cisco systems
Software Engineer
San Jose CA

Guaranteed order for syncing Records

[suraj pasuparthy]

Hello Experts,
I had a question

We have a multi DC cluster for cassandra and wanted to confirm one behavior.
Are the records order maintained while syncing to the backup datacenter?
What i mean is, if say, Record A is written to a Table A and Record B is
written to Table B on Datacenter 1, Does cassandra ensure that first Record
A is synced to Table A in Datacenter 2 and then the Record B syncs to table
B ?

Is there a possibility of "out of order " syncs between datacenters ?

-- 
Suraj Pasuparthy

Re: Replication issue with Multi DC setup in cassandra

[suraj pasuparthy]

Yes is see them in the datacenter's data directories.. infact i see then
even after i bring down the interface between the 2 DC's which further
confirms that a local copy is maintained in the DC that was not configured
in the strategy ..
its quite important that we block the info for this keyspace from
replicating :(.. not sure why this does not work

Thanks
Suraj

On Tue, May 16, 2017 at 3:06 PM Nitan Kainth <ni...@bamlabs.com> wrote:

> check for datafiles on filesystem in both DCs.
>
> On May 16, 2017, at 4:42 PM, suraj pasuparthy <suraj.pasupar...@gmail.com>
> wrote:
>
> So i though the same,
> I see the data via the CQLSH in both the datacenters. consistency is set
> to LQ
>
> thanks
> -Suraj
>
> On Tue, May 16, 2017 at 2:19 PM, Nitan Kainth <ni...@bamlabs.com> wrote:
>
>> Do you see data on other DC or just directory structure? Directory
>> structure would populate because it is DDL but inserts shouldn’t populate,
>> ideally.
>>
>> On May 16, 2017, at 3:19 PM, suraj pasuparthy <suraj.pasupar...@gmail.com>
>> wrote:
>>
>> elp me fig
>>
>>
>>
>
>
> --
> Suraj Pasuparthy
>
> cisco systems
> Software Engineer
> San Jose CA
>
>
>
>
>
>

Re: Replication issue with Multi DC setup in cassandra

[suraj pasuparthy]

So i though the same,
I see the data via the CQLSH in both the datacenters. consistency is set to
LQ

thanks
-Suraj

On Tue, May 16, 2017 at 2:19 PM, Nitan Kainth <ni...@bamlabs.com> wrote:

> Do you see data on other DC or just directory structure? Directory
> structure would populate because it is DDL but inserts shouldn’t populate,
> ideally.
>
> On May 16, 2017, at 3:19 PM, suraj pasuparthy <suraj.pasupar...@gmail.com>
> wrote:
>
> elp me fig
>
>
>


-- 
Suraj Pasuparthy

cisco systems
Software Engineer
San Jose CA

Replication issue with Multi DC setup in cassandra

[suraj pasuparthy]

Hello,
I am tying to find a way to PREVENT just one of my keyspaces to not sync to
the other datacenter.

I have 2 datacenters setup this way :

Datacenter: DC:4.4.4.4

==

Status=Up/Down

|/ State=Normal/Leaving/Joining/Moving

--  Address  Load   Tokens   Owns (effective)  Host ID
  Rack

UN  4.4.4.4  189.42 KiB  32   100.0%
939f5965-f9d5-4673-b1a4-29fa5ecae0f9  rack1

Datacenter: DC:4.4.4.5

==

Status=Up/Down

|/ State=Normal/Leaving/Joining/Moving

--  Address  Load   Tokens   Owns (effective)  Host ID
  Rack

UN  4.4.4.5  218.29 KiB  32   100.0%
c0d1d859-7ae9-4ce9-a50f-ea316963dbb1  rack1

all my keyspaces have 1 copy in each DC and it works like a charm.

however, I have ONE keyspace that i do not want to sync. and i define the
keyspace this way:

CREATE KEYSPACE nosync WITH replication = {'class':
'NetworkTopologyStrategy', 'DC:4.4.4.4': '1', 'DC:4.4.4.5': '0'}  AND
durable_writes = true;
and i still see that keyspace show up in DC:4.4.4.5
i even tried

CREATE KEYSPACE nosync WITH replication = {'class':
'NetworkTopologyStrategy', 'DC:4.4.4.4': '1'}  AND durable_writes = true;

Same issue, i still see the keyspace show up in the DC:4.4.4.5

Could anyone help me figure this out?

Cheers

-Suraj

Re: Decommissioned node cluster shows as down

[suraj pasuparthy]

Yes, you have to run a nodetool removenode to decomission completely.. this
will also allow another node with the same ip different HashId to join the
cluster..

Thanks
-suraj
On Tue, May 16, 2017 at 9:01 AM Mark Furlong  wrote:

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> completed the decommission process and is no longer communicating with the
> rest of the cluster. However when I run a nodetool status on any node in
> the cluster it shows
>
> the node as ‘DN’. Why is this and should I just run a removenode now?
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> *Thanks,*
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> *Mark Furlong*
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> Sr. Database Administrator
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> *mfurl...@ancestry.com *
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> M: 801-859-7427
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> O: 801-705-7115
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> 1300 W Traverse Pkwy
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> Lehi, UT 84043
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Help with cassandra triggers

[suraj pasuparthy]

Hello
We have a usecase where we need to support triggers with multiple
datacenters.
The use case is we need is
1) Data is written into DC1.
2) The Sync configured will sync the data to DC2
3) when the data is written into DC2, we need a trigger to fire on DC2.

I have tested the triggers for a local write. But i do not see the trigger
on sync.
Could anyone please help me out with this ?

thanks
Suraj