On 12/03/2014 05:39 PM, Logan Barfield wrote: > I'm not sure if this is already in place, but if not I think pool quotas > should be exposed in the same way as pool size so Libvirt can pick up on > them. > Yes, that would be ideal indeed. > We currently run several KVM hypervisors backed by Ceph RBD. We have a > CRUSH ruleset that defines SSD backed servers for RBD, and high capacity > HDD backed servers for RadosGW. > > Right now when adding our RBD pool via Libvirt it sees the entire cluster's > capacity, even though the actual pool capacity is much lower. This means > that any deployment tools that look at the available capacity when creating > VMs can't be relied upon, and we have to continually track usage manually > (we audit it anyway, but that should be in addition to built-in checks). > We can currently work around this by manually setting the capacity in the > deployment tool, but fixing it at the source seems like a much better > option. > > Obviously capacity can't be automatically estimated from the CRUSH ruleset, > but with the recent addition of pool quotas it would be useful to let > Libvirt (and other clients) pull the quota size so we could set them as > needed. > > Some changes will need to be made on the Libvirt side as well, but the > functionality has to be implemented in Ceph first. > The main problem here is that I currently don't see a way in librados to fetch this information. rados_pool_stat_t in librados.h does not expose a quota or anything similar. So what currently happens is that Libvirt does a cluster stat() in librados and fetches how large the cluster is. If librados exposes a way to get the quota from a pool it would be very simple to fix this in Libvirt. > I have opened an issue in the tracker for this: > http://tracker.ceph.com/issues/10226 > I'll assign this to myself. > If this functionality already exists I'll close the issue and work on > things from the Libvirt side. > > > Thank You, > > Logan Barfield > Tranquil Hosting > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Wido den Hollander 42on B.V. Ceph trainer and consultant Phone: +31 (0)20 700 9902 Skype: contact42on -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
