On Thu, Oct 17, 2013 at 6:19 AM, Robert van Leeuwen <Robert.vanLeeuwen@xxxxxxxxxxxxx> wrote: > Hi, > > I'm wondering how Ceph behaves when there are multiple sources writing heavily to the same pool (e.g. Openstack nova compute) > Will each get its own "fair share" or will a very heavy user impact all others? Ceph doesn't do any real QoS, so a heavy user can impact others in terms of request latencies. The OSD makes some attempts to dispatch client messages fairly once they arrive, though, so a single heavy writer can't starve out other users. (IOPs are distributed via round-robin, which with standard striping policies are going to be the dominating expense.) > Are there ways to tune this? I think there's some stuff you can apply to librbd at the client level (Josh?), but there's unfortunately not much you can do server-side right now. -Greg Software Engineer #42 @ http://inktank.com | http://ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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