I think smaller clusters get chocked up with the default backfill. I've seen latency on a four node cluster with 10 OSD each improve by setting osd_max_backfills to 2. I would try lowering it and see if it helps.
Also, if you are running both cluster and VM traffic on the same network, you could get congestion especially on a 1 Gb network. Robert LeBlanc On Fri, Dec 19, 2014 at 9:33 AM, Nico Schottelius < nico-ceph-us...@schottelius.org> wrote: > > Hello, > > another issue we have experienced with qemu VMs > (qemu 2.0.0) with ceph-0.80 on Ubuntu 14.04 > managed by opennebula 4.10.1: > > The VMs are completly frozen when rebalancing takes place, > they do not even respond to ping anymore. > > Looking at the qemu processes they are in state "Sl". > > Is this a known problem / have others seen this behaviour? > > I have not yet tuned any backfilling parameters and it is a > cluster of 3 hosts with one host having 6 osds and two 1 one (so 8 osds > in total). > > Our qemu runs with these rbd related options: > > qemu-system-x86_64 ... -drive > > file=rbd:one/one-38:id=libvirt:key=...:auth_supported=cephx\;none:mon_host= > kaffee.private.ungleich.ch\;wein.private.ungleich.ch\; > tee.private.ungleich.ch,if=none,id=drive-ide0-0-0,format=raw,cache=none > > Cheers, > > Nico > > -- > New PGP key: 659B 0D91 E86E 7E24 FD15 69D0 C729 21A1 293F 2D24 > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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