> So .. the idea was that ceph would provide the required clustered filesystem > element, > and it was the only FS that provided the required "resize on the fly and > snapshotting" things that were needed. > I can't see it working with one shared lun. In theory I can't see why it > couldn't work, but have no idea how the likes of > vmfs achieve the locking across the cluster with single luns, I certainly > don't know of something within linux that could do it.
Linux also has a few clustered filesystems e.g. GFS2 or OCFS. I'm not sure how suited these are for fileservers though since they will have to lots of locking of files. > I guess I could see a clustered FS like Ceph providing something similar to a > software raid 1, where > two volumes were replicated and access from a couple of hosts point to the > two different backend "halves" of the raid via a load balancer? * Ceph RDB (which is stable) just gives you a block device. This is "similar" to ISCSI except that the data is distributed accross x ceph nodes. Just as ISCSI you should mount this on two locations unless you run a clustered filesystem (e.g. GFS / OCFS) * CephFS gives you a clustered posix filesystem. You can run NFS/CTDB directly on top of this. In theory this is what you are looking for except that it isn't fully mature yet. > The other option is to ditch the HA features and just go with samba on the > top of zfs, which could still provide the snapshots we need, > although it's a step backwards, but then I don't like the sound of the ctdb > complexity or performance problems cited. > I guess people just don't do HA in file sharing roles.. Most clusters will be HA but not active-active. As mentioned above it is possible but you might run into performance issues with file locking. (Its been a while since I did things with GFS) > What about NFS or the like for VM provision though - it's pretty similar just > with CTDB bolted on top? With NFS you have the same issues. The posix filesystem it runs on needs to be clustered. When there is a ceph driver for vmware (not sure what the status is but I think they are working on it) you could directly plugin your hypervisors into Ceph. Still, running it ceph on a SAN still defeats the purpose, might as well just use ISCSI + vmfs directly on the SAN. Cheers, Robert _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
