On Tue, Jun 11, 2013 at 2:35 PM, Bryan Stillwell <bstillwell@xxxxxxxxxxxxxxx> wrote: > I have a cluster I originally built on argonaut and have since > upgraded it to bobtail and then cuttlefish. I originally configured > it with one node for both the mds node and mon node, and 4 other nodes > for hosting osd's: > > a1: mon.a/mds.a > b1: osd.0, osd.1, osd.2, osd.3, osd.4, osd.20 > b2: osd.5, osd.6, osd.7, osd.8, osd.9, osd.21 > b3: osd.10, osd.11, osd.12, osd.13, osd.14, osd.22 > b4: osd.15, osd.16, osd.17, osd.18, osd.19, osd.23 > > Yesterday I added two more mon nodes and moved mon.a off of a1 so it > now looks like: > > a1: mds.a > b1: osd.0, osd.1, osd.2, osd.3, osd.4, osd.20 > b2: mon.a, osd.5, osd.6, osd.7, osd.8, osd.9, osd.21 > b3: mon.b, osd.10, osd.11, osd.12, osd.13, osd.14, osd.22 > b4: mon.c, osd.15, osd.16, osd.17, osd.18, osd.19, osd.23 > > What I would like to do is move mds.a to server b1 so I can power-off > a1 and bring up b5 with another 6 osd's (power in my basement is at a > premium), but I'm not finding much in the way of documentation on how > to do that. I found some docs on doing it with ceph-deploy, but since > I built this a while ago I haven't been using ceph-deploy (and I > haven't had a great experience using it for building a new cluster > either). > > Could some one point me at some docs on how to do this? Also should I > be running with multiple mds nodes at this time? > > Thanks, > Bryan You should not run more than one active MDS (less stable than a single-MDS configuration, bla bla bla), but you can run multiple daemons and let the extras serve as a backup in case of failure. The process for moving an MDS is pretty easy: turn on a daemon somewhere else, confirm it's connected to the cluster, then turn off the old one. Doing it that way will induce ~30 seconds of MDS inavailability while it times out, but on cuttlefish you should be able to force an instant takeover if the new daemon uses the same name as the old one (I haven't worked with this much myself so I might be missing a detail; if this is important you should check). (These relatively simple takeovers are thanks to the MDS only storing data in RADOS, and are one of the big design considerations in the system architecture). -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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