You can use multiple "steps" in your crush map in order to do things like choose two different hosts then choose a further OSD on one of the hosts and do another replication so that you can get three replicas onto two hosts without risking ending up with three replicas on a single node. On 28/07/2014 18:14, Craig Lewis wrote: > That's expected. You need > 50% of the monitors up. If you only have > 2 machines, rebooting one means that 50% are up, so the cluster halts > operations. That's done on purpose to avoid problems when the cluster > is divided in exactly half, and both halves continue to run thinking > the other half is down. Monitors don't need a lot of resources. I'd > recommend that you add a small box as a third monitor. A VM is fine, > as long as it has enough IOPS to it's disks. > > It's best to have 3 storage nodes. A new, out of the box install > tries to store data on at least 3 separate hosts. You can lower the > replication level to 2, or change the rules so that it will store data > on 3 separate disks. It might store all 3 copies on the same host > though, so lowering the replication level to 2 is probably better. > > I think it's possible to require data stored on 3 disks, with 2 of the > disks coming from different nodes. Editing the CRUSH rules is a bit > advanced: http://ceph.com/docs/master/rados/operations/crush-map/ > > > > > On Mon, Jul 28, 2014 at 9:59 AM, Don Pinkster <don at pinkster.me > <mailto:don at pinkster.me>> wrote: > > Hi, > > Currently I am evalutating multiple distributed storage solutions > with an S3-like interface. > We have two huge machines with big amounts of storage. Is it > possible to let these two behave exactly the same with Ceph? My > idea is runninng both MON and OSD on these two machines. > > With quick tests the cluster is degrated after a reboot of 1 host > and is not able to recover from the reboot. > > Thanks in advance! > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com <mailto:ceph-users at lists.ceph.com> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140728/bdec4eb7/attachment.htm>
 |