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From Jason Wee <peich...@gmail.com>
Subject Re: High CPU load
Date Mon, 20 Jul 2015 07:18:40 GMT
just a guess, gc?

On Mon, Jul 20, 2015 at 3:15 PM, Marcin Pietraszek <mpietraszek@opera.com>
wrote:

> Hello!
>
> I've noticed a strange CPU utilisation patterns on machines in our
> cluster. After C* daemon restart it behaves in a normal way, after a
> few weeks since a restart CPU usage starts to raise. Currently on one
> of the nodes (screenshots attached) cpu load is ~4. Shortly before
> restart load raises to ~15 (our cassandra machines have 16 cpus).
>
> In that cluster we're using bulkloading from hadoop cluster with 1400
> reducers (200 parallel bulkloading tasks). After such session of heavy
> bulkloading number of pending compactions is quite high but it's able
> to clear them before next "bulkloading session". We're also tracking
> number of pending compactions and during most of the time it's 0.
>
> On our machines we do have a few gigs of free memory ~7GB (17GB used),
> also it seems like we aren't IO bound.
>
> Screenshots from our zabbix with CPU utilisation graphs:
>
> http://i60.tinypic.com/xas8q8.jpg
> http://i58.tinypic.com/24pifcy.jpg
>
> Do you guys know what could be causing such high load?
>
> --
> mp
>

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