On Tue, Apr 09, 2013 at 10:09:11AM +0200, Sebastien Han wrote: > So the memory is _not_ saved, only the disk is. Note that it's always hard to > make consistent snapshot. I assume that freezing the filesystem itself is the > only solution to have a consistent snapshot, and still this doesn't mean that > your application's data are consistent , in term of commits for instance with > a database. I don't know which applications do you run but at the end, you > might consider to stop some daemon as well, freeze the fs (to be sure), take > your snapshot, unfreeze, start your daemon. You could reach 100% consistency > with this method… I guess :)
I believe in journaling filesystems and their ability to recover from 'crashes' like these. So what I do is just take a snapshot of a running vm. If you re-mount that snapshot (e. g. in a rbd child) the journal replay assures a consistent filesystem. Database systems are designed to recover from power loss, this is nothing different than a power loss. And pg_dump or mysql_dumps (or whatever_dump) are a good habit anyway, if the database is small enough. I've written up how I do ceph backups here: http://www.wogri.at/Ceph-VM-Backup.339.0.html Be aware that disabling rbd_cache in libvirt for now is more safe in terms of stability than enabling it (patches are out there but not in the OS packages yet). > Cheers. my 2c Wolfgang -- http://www.wogri.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
