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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: [Cassandra] Expanding a Cassandra cluster
Date Wed, 12 Jun 2013 12:03:43 GMT
We run it concurrently each RF nodes (If RF = 3, we run it on 3 waves). If
the node is busy cleaning up, then the client will time out and ask to an
other node having a copy of the data and that is not being cleaned up.

"Will node tool cleanup consume lot of IO and CPU even though there is
nothing to clean"

Yes, I think so, since you have to check that you have nothing to clean...
I think there is no case that need a regular cleanup anyway.


2013/6/12 Michal Michalski <michalm@opera.com>

>  What will happen if I add nodetool cleanup to run periodically (similar
>> to nodetool repair) ? Will node tool cleanup consume lot of IO and CPU even
>> though there is nothing to clean ?
>>
>
> Why would you need doing so?
>
> M.
>
>
>
>> Thank you
>> Emalayan
>>
>>
>> ______________________________**__
>>   From: Robert Coli <rcoli@eventbrite.com>
>> To: user@cassandra.apache.org; Emalayan Vairavanathan <
>> svemalayan@yahoo.com>
>> Sent: Monday, 10 June 2013 5:15 PM
>> Subject: Re: [Cassandra] Expanding a Cassandra cluster
>>
>>
>> On Mon, Jun 10, 2013 at 3:13 PM, Emalayan Vairavanathan
>> <svemalayan@yahoo.com> wrote:
>>
>>> I suspect that nodetool cleanup is IO intensive. So running nodetool
>>> cleanup
>>> concurrently on the entire cluster may have a significantly impact the IO
>>> performance of applications.
>>>
>>
>> cleanup is a specific kind of compaction, and as such respects the
>> compaction throughput throttle.
>>
>> The compaction throughput throttle is designed to prevent compaction
>> from negatively impacting the performance of things-not-compaction. If
>> you notice that cleanup compaction on all or most nodes consumes too
>> much i/o, reduce the throttle value.
>>
>> =Rob
>>
>>
>

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