just a guess, gc? On Mon, Jul 20, 2015 at 3:15 PM, Marcin Pietraszek <mpietras...@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 >
