On 5/23/14 09:30 , Fabian Zimmermann wrote: > Hi, > >> Am 23.05.2014 um 17:31 schrieb "Wido den Hollander" <wido at 42on.com>: >> >> I wrote a blog about this: http://blog.widodh.nl/2014/03/safely-backing-up-your-ceph-monitors/ > so you assume restoring the old data is working, or did you proof this? > > I did some of the same things, but never tested a restore (http://permalink.gmane.org/gmane.comp.file-systems.ceph.user/3087). There is a discussion, but I can't figure out how to get gmane to show me the threaded version from a google search. I stopped doing the backups, because they seemed rather useless. The monitors have a snapshot of the cluster state right now. If you ever need to restore a monitor backup, you're effectively rolling the whole cluster back to that point in time. What happens if you've added disks after the backup? What happens if a disk has failed after the backup? What happens if you write data to the cluster after the backup? What happens if you delete data after the backup, and it gets garbage collected? All questions that can be tested and answered... with a lot of time and experimentation. I decided to add more monitors and stop taking backups. I'm still thinking about doing manual backups before a major ceph version upgrade. In that case, I'd only need to test the write/delete cases, because I can control the the add/remove disk cases. The backups would only be useful between restarting the MON and the OSD processes though. I can't really backup the OSD state[1], so once they're upgraded, there's no going back. 1: ZFS or Btrfs snapshots could do this, but neither one are recommended for production. I do plan to make snapshots once either FS is production ready. LVM snapshots could do it, but they're such a pain that I never bothered. And I have the scripts I used to use to make LVM snapshots of MySQL data directories. -- *Craig Lewis* Senior Systems Engineer Office +1.714.602.1309 Email clewis at centraldesktop.com <mailto:clewis at centraldesktop.com> *Central Desktop. Work together in ways you never thought possible.* Connect with us Website <http://www.centraldesktop.com/> | Twitter <http://www.twitter.com/centraldesktop> | Facebook <http://www.facebook.com/CentralDesktop> | LinkedIn <http://www.linkedin.com/groups?gid=147417> | Blog <http://cdblog.centraldesktop.com/> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140523/d0e153b7/attachment.htm>
 |