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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: (unofficial) Community Poll for Production Operators : Repair
Date Tue, 14 May 2013 07:42:10 GMT
Hi Rob,

1) 1.2.2 on 6 to 12 EC2 m1.xlarge
2) Quorum R&W . Almost no deletes (just some TTL)
3) Yes
4) On each node once a week (rolling repairs using crontab)
5) The only behavior that is quite odd or unexplained to me is why a repair
doesn't fix a counter mismatch between 2 nodes. I mean when I read my
counters with a CL.One I have inconsistency (the counter value may change
anytime I read it, depending, I guess, on what node I read from. Reading
with CL.Quorum fixes this bug, but the data is still wrong on some nodes.
About performance, it's quite expensive to run a repair but doing it in a
low charge period and in a rolling fashion works quite well and has no
impact on the service.

Hope this will help somehow. Let me know if you need more information.

Alain



2013/5/10 Robert Coli <rcoli@eventbrite.com>

> Hi!
>
> I have been wondering how Repair is actually used by operators. If
> people operating Cassandra in production could answer the following
> questions, I would greatly appreciate it.
>
> 1) What version of Cassandra do you run, on what hardware?
> 2) What consistency level do you write at? Do you do DELETEs?
> 3) Do you run a regularly scheduled repair?
> 4) If you answered "yes" to 3, what is the frequency of the repair?
> 5) What has been your subjective experience with the performance of
> repair? (Does it work as you would expect? Does its overhead have a
> significant impact on the performance of your cluster?)
>
> Thanks!
>
> =Rob
>

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