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From Kunal <kunal.v...@gmail.com>
Subject Re: Unpair cassandra datacenters
Date Tue, 23 Apr 2019 17:17:44 GMT
Thanks Sandeep for your reply. Let me try out the steps you suggested. I
will let you know. Appreciate your help.


Regards,
Kunal Vaid

On Mon, Apr 22, 2019 at 4:18 PM Sandeep Nethi <nethisandeeps@gmail.com>
wrote:

> Hi Kunal,
>
> The simple solution for this case would be as follows,
>
> 1. Run *Full repair.*
> 2. Add firewall to block network on port 7000(,7001 if ssl enabled)
> between two datacenter nodes.
> 3. Check the status of cassandra cluster from both data centers, each DC
> must show down node status of another DC nodes after the firewall change.
> 4. Change replication factor for all keyspaces on each data center.
> 5. Start decommissioning nodes from each datacenter (Should be removenode
> in this case).
> 6. Update seeds list on each datacenter to local datacenter nodes and
> perform a rolling restart.
>
> Hope this helps, Try to test this scenario on non-prod system first.
>
> Thanks,
> Sandeep
>
> On Tue, Apr 23, 2019 at 11:00 AM Kunal <kunal.vaid@gmail.com> wrote:
>
>> HI Marc,
>>
>> Appreciate your prompt response.
>>
>> Yes we are starting datacenter B from scratch. We tried using cluster
>> name change on side B and it works but our requirement says we can not
>> change cluster name because during our product's major or patch release,
>> the scripts expect cluster name to be the same.
>> .
>> On datacenter B , we are changing the seeds nodes. On datacenter A , we
>> are changing the seeds nodes in cassandra.yml but that will be picked up
>> during cassandra restart only but we can not have downtime for datacenter
>> A. It has to be up all the time.
>>
>>
>> Regards,
>> Kunal Vaid
>>
>>
>> On Mon, Apr 22, 2019 at 3:49 PM Marc Selwan <marc.selwan@datastax.com>
>> wrote:
>>
>>> Hi Kunal,
>>>
>>> Did you edit the cassandra.yaml file in each data center to remove the
>>> seed nodes? On which ever data center is starting from scratch (I think
>>> it's B in your case), you may want to also change the cluster name.
>>>
>>> Best,
>>> *Marc Selwan | *DataStax *| *PM, Server Team *|* *(925) 413-7079* *|*
>>> Twitter <https://twitter.com/MarcSelwan>
>>>
>>> *  Quick links | *DataStax <http://www.datastax.com> *| *Training
>>> <http://www.academy.datastax.com> *| *Documentation
>>> <http://www.datastax.com/documentation/getting_started/doc/getting_started/gettingStartedIntro_r.html>
>>>  *| *Downloads <http://www.datastax.com/download>
>>>
>>>
>>>
>>> On Mon, Apr 22, 2019 at 3:38 PM Kunal <kunal.vaid@gmail.com> wrote:
>>>
>>>> Hi Friends,
>>>>
>>>> I need small help in unpairing two datacenters.
>>>> We have 2 datacenters (say A and B ) with 3 nodes in each datacenter.
>>>> We want to remove one whole data center (B) (3 nodes) from the other one
>>>> (B). basically, want to unpair both datacenter and want to use them both
>>>> individually.
>>>> We are trying this using nodetool decommission and it is removing the 3
>>>> nodes from B datacenter. But when we are trying to bring up datacenter B
to
>>>> use it separately from Datacenter A, it is joining back to datacenter A.
We
>>>> noticed in debug.log, nodes from datacenter A keeps looking for nodes in
>>>> datacenter B and getting connection refused error when the nodes of
>>>> datacenter B are down, but as soon as nodes comes back, they are joining
to
>>>> the cluster.
>>>> We don't want nodes from datacenter B to join datacenter A once they
>>>> are decommissioned.
>>>>
>>>> Can you please let me know if i am missing anything.
>>>>
>>>> Thanks in advance.
>>>>
>>>> Regards,
>>>> Kunal Vaid
>>>>
>>>
>>
>> --
>>
>>
>>
>> Regards,
>> Kunal Vaid
>>
>

-- 



Regards,
Kunal Vaid

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