Hi John, Thanks for the reply! Yes, I agree Ceph is exciting! Keep up the good work!
> Using librbd, as you've pointed out, doesn't run afoul of potential Linux > kernel deadlocks; however, you normally wouldn't encounter this type of > situation in a production cluster anyway as you'd likely never use the same > host for client and server components. We're planning to do this (host VMs on Ceph OSDs). What should we be wary of other than the loopback deadlock problem? > See: http://ceph.com/docs/master/rbd/rbd-openstack/ and notice that cloud > platforms generally feed Ceph block devices via QEMU and libvirt to the > cloud computing platform. At the moment we're using ganeti, which can either librbd or module rbd, hence my questions. :) Eventually I'll post performance comparisons for those two options. > In other words, you create a "golden > image" that you can snapshot and then use copy-on-write cloning to bring up > VMs using an RBD-based image snapshot quickly. > OS image sizes are often sizable. So downloading them each time would be > time-consuming and slow. If you can do that once and snapshot the image; > then, clone the snapshot, that's dramatically faster. Good idea! We haven't really explored Ceph's snapshotting / cloning etc. Thanks, Chad. _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
