>>OK, so I need to change ceph.conf on the compute nodes? yes. >>Do the VMs using RBD images need to be restarted at all? I think yes. >>Anything changed in the virsh XML for the nodes? you need to add cache=writeback for your disks If you use qemu > 1.2, no need to add "rbd cache = true" to ceph .conf :) http://ceph.com/docs/next/rbd/qemu-rbd/ ----- Mail original ----- De: "Graeme Lambert" <glambert@xxxxxxxxxxx> À: "Alexandre DERUMIER" <aderumier@xxxxxxxxx> Cc: ceph-users@xxxxxxxxxxxxxx Envoyé: Jeudi 6 Février 2014 12:03:00 Objet: Re: RBD Caching - How to enable? Hi Alexandre, OK, so I need to change ceph.conf on the compute nodes? Do the VMs using RBD images need to be restarted at all? Anything changed in the virsh XML for the nodes? Best regards Graeme On 06/02/14 10:50, Alexandre DERUMIER wrote: <blockquote> <blockquote> The documentation states that setting "rbd cache = true" in [global] enables it, but doesn't elaborate on whether you need to restart any Ceph processe </blockquote> It's on the client side ! (so no need to restart ceph daemons) ----- Mail original ----- De: "Graeme Lambert" <glambert@xxxxxxxxxxx> À: ceph-users@xxxxxxxxxxxxxx Envoyé: Jeudi 6 Février 2014 11:43:56 Objet: RBD Caching - How to enable? Hi, I've got a few VMs in Ceph RBD that are running very slowly - presumably down to a backfill after increasing the pg_num of a big pool. Would RBD caching resolve that issue? If so, how do I enable it? The documentation states that setting "rbd cache = true" in [global] enables it, but doesn't elaborate on whether you need to restart any Ceph processes. Is that literally all that is needed or is there more to it than that? </blockquote> _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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