Hi Ashley, On Monday, October 24, 2016, Ashley Merrick <ash...@amerrick.co.uk> wrote:
> Hello, > > Thanks both for your responses, defiantly looking at collectd + graphite, > just wanted to see what overheads where like, far from in a situation that > would choke the cluster but wanted to check first. > > I run ceph -s with json output, parse that (with e.g. Perl, or you can use Python etc) and store in mysql database. This provides a few snapshots and simple at a glance analysis. Overhead is practically none. For OSDs things are trickier, but for simplicity's sake we run iostat for a few cycles and parse that output, then aggregate. Collectd and graphite look really nice. Regards, Alex > Thanks, > Ashley > > -----Original Message----- > From: Christian Balzer [mailto:ch...@gol.com <javascript:;>] > Sent: 24 October 2016 11:04 > To: ceph-users@lists.ceph.com <javascript:;> > Cc: John Spray <jsp...@redhat.com <javascript:;>>; Ashley Merrick < > ash...@amerrick.co.uk <javascript:;>> > Subject: Re: [ceph-users] Monitoring Overhead > > > Hello, > > On Mon, 24 Oct 2016 10:46:31 +0100 John Spray wrote: > > > On Mon, Oct 24, 2016 at 4:21 AM, Ashley Merrick <ash...@amerrick.co.uk > <javascript:;>> wrote: > > > Hello, > > > > > > > > > > > > This may come across as a simple question but just wanted to check. > > > > > > > > > > > > I am looking at importing live data from my cluster via ceph -s > > > e.t.c into a graphical graph interface so I can monitor performance > > > / iops / e.t.c overtime. > > > > > > > > > > > > I am looking to pull this data from one or more monitor nodes, when > > > the data is retrieved for the ceph -s output is this information > > > that the monitor already has locally or is there an overhead that is > > > applied to the whole cluster to retrieve this data every time the > command is executed? > > > > It's all from the local state on the mons, the OSDs aren't involved at > > all in responding to the status command. > > > That said, as mentioned before on this ML, the output of "ceph -s" is a > sample from a window and only approaching something reality if sampled and > divided of a long period. > > If you need something that involves "what happened on OSD x at time y", > collectd and graphite (or deviations of if) are your friends, but they do > cost you a CPU cycle or two. > OTOH, if your OSDs or MONs were to choke from that kind of monitoring, > you're walking on very thin ice already. > > Christian > > > Cheers, > > John > > > > > > > > > > > > > > Reason I ask is I want to make sure I am not applying unnecessary > > > overhead and load onto all OSD node’s to retrieve this data at a > > > near live view, I fully understand it will apply a small amount of > > > load / CPU on the local MON to process the command, I am more > interesting in overall cluster. > > > > > > > > > > > > Thanks, > > > > > > Ashley > > > > > > > > > _______________________________________________ > > > ceph-users mailing list > > > ceph-users@lists.ceph.com <javascript:;> > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com <javascript:;> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > -- > Christian Balzer Network/Systems Engineer > ch...@gol.com <javascript:;> Global OnLine Japan/Rakuten > Communications > http://www.gol.com/ > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com <javascript:;> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- -- Alex Gorbachev Storcium
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