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From Ankit Gadhiya <ankitgadh...@gmail.com>
Subject Re: Query timeouts after Cassandra Migration
Date Fri, 07 Feb 2020 02:10:28 GMT
Thanks Eric.
So do you advise copying tokens in such cases ? What procedure is advisable
?

Latency increased on target cluster. I’d double check on storage disks but
it should be same.


— Ankit

On Thu, Feb 6, 2020 at 9:07 PM Erick Ramirez <flightctlr@gmail.com> wrote:

> I didn’t copy tokens since it’s an identical cluster and we have RF as 3
>> on 3 node cluster. Is it still needed , why?
>>
>
> In C*, same number of nodes alone isn't enough. Clusters aren't really
> identical unless token assignments are the same. In your case though since
> each node has a full copy of the data (RF = N nodes), they "appear"
> identical.
>
> I recently migrated Cassandra keyspace data from one Azure cluster (3
>> Nodes) to another (3 nodes different region) using simple sstable copy.
>> Post this , we are observing overall response time has increased and
>> timeouts every 20 mins.
>>
>
>  You mean the response time on the source cluster increased? Or the
> destination cluster? I can't see how the copy could affect latency unless
> you're using premium storage disks and you've maxed out the throughput on
> them. For example, P30 disks are capped at 200MB/s.
>
> Do I need to copy anything from system*
>
>
> No, system tables are local to a node. Only ever copy the application
> keyspaces. Cheers!
>
-- 
*Thanks & Regards,*
*Ankit Gadhiya*

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