On Thu, 4 Oct 2012, Bryan K. Wright wrote:
> Hi Greg,
>
> g...@inktank.com said:
> > I think I'm with Mark now ? this does indeed look like too much random IO
> > for
> > the disks to handle. In particular, Ceph requires that each write be synced
> > to
> > disk before it's considered complete, which rsync definitely doesn't. In the
> > filesystem this is generally disguised fairly well by all the caches and
> > such
> > in the way, but this use case is unfriendly to that arrangement.
>
> > However, I am particularly struck by seeing one of your OSDs at 96% disk
> > utilization while the others remain <50%, and I've just realized we never
> > saw
> > output from ceph -s. Can you provide that, please?
>
> Here's the ceph -s output:
>
> health HEALTH_OK
> monmap e1: 3 mons at
> {0=192.168.1.31:6789/0,1=192.168.1.32:6789/0,2=192.168.1
> .33:6789/0}, election epoch 2, quorum 0,1,2 0,1,2
> osdmap e24: 4 osds: 4 up, 4 in
> pgmap v8363: 960 pgs: 960 active+clean; 15099 MB data, 38095 MB used,
> 74354
> GB / 74391 GB avail
> mdsmap e25: 1/1/1 up {0=2=up:active}, 2 up:standby
>
> The OSD disk utilization seems to vary a lot during these
> benchmarks. My recollection is that each of the OSD hosts sometimes
> sees near-100% utilization.
Can you also include 'ceph osd tree', 'ceph osd dump', and 'ceph pg dump'
output? So we can make sure CRUSH is distributing things well?
Thanks!
sage
>
> Bryan
>
>
> --
> ========================================================================
> Bryan Wright |"If you take cranberries and stew them like
> Physics Department | applesauce, they taste much more like prunes
> University of Virginia | than rhubarb does." -- Groucho
> Charlottesville, VA 22901|
> (434) 924-7218 | br...@virginia.edu
> ========================================================================
>
>
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