Hi Daniel, Many thanks, I will keep this in mind while performing the updates in the future. Note to documentation manager - perhaps it makes sens to add this solution as a note/tip to the Upgrade section of the release notes? Andrei ----- Original Message ----- > From: "Daniel Swarbrick" <daniel.swarbrick@xxxxxxxxxxxxxxxx> > To: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> > Cc: "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx> > Sent: Wednesday, 22 June, 2016 17:09:48 > Subject: Re: [ceph-users] cluster down during backfilling, Jewel tunables and client IO optimisations > On 22/06/16 17:54, Andrei Mikhailovsky wrote: >> Hi Daniel, >> >> Many thanks for your useful tests and your results. >> >> How much IO wait do you have on your client vms? Has it significantly increased >> or not? >> > > Hi Andrei, > > Bearing in mind that this cluster is tiny (four nodes, each with four > OSDs), our metrics may not be that meaningful. However, on a VM that is > running ElasticSearch, collecting logs from Graylog, we're seeing no > more than about 5% iowait for a 5s period, and most of the time it's > below 1%. This VM is really not writing a lot of data though. > > The cluster as a whole is peaking at only about 1200 write op/s, > according to ceph -w. > > Executing a "sync" in a VM does of course have a noticeable delay due to > the recovery happening in the background, but nothing is waiting for IO > long enough to trigger the kernel's 120s timer / warning. > > The recovery has been running for about four hours now, and is down to > 20% misplaced objects. So far we have not had any clients block > indefinitely, so I think the migration of VMs to Jewel-capable > hypervisors did the trick. > > Best, > Daniel > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
