Hi, I think you?re rather brave (sorry, foolish) to store the mon data dir in ramfs. One power outage and your cluster is dead. Even with good backups of the data dir I wouldn't want to go through that exercise. Saying that, we had a similar disk-io-bound problem with the mon data dirs, and solved it by moving the mons to SSDs. Maybe in your case using the cfq io scheduler would help, since at least then the OSD and MON processes would get fair shares of the disk IOs. Anyway, to backup the data dirs, you need to stop the mon daemon to get a consistent leveldb before copying the data to a safe place. Cheers, Dan -- Dan van der Ster || Data & Storage Services || CERN IT Department -- On 23 May 2014, at 15:45, Fabian Zimmermann <f.zimmermann at xplosion.de> wrote: > Hello, > > I?m running a 3 node cluster with 2 hdd/osd and one mon on each node. > Sadly the fsyncs done by mon-processes eat my hdd. > > I was able to disable this impact by moving the mon-data-dir to ramfs. > This should work until at least 2 nodes are running, but I want to implement some kind of disaster recover. > > What?s the correct way to backup mon-data - if there is any? > > Thanks, > > Fabian > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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