[pardon if a duplicate - doesn't seem to have gone through the first time, earlier today] Hi Folks, We've been running a 2-node, high-availability cluster - basically xen w/ pacemaker and DRBD for replicating disks. We recently purchased 2 additional, servers, and I'm thinking about combining all 4 machines into a 4-node cluster - which takes us out of DRBD space and requires some other kind of filesystem replication. Gluster, Ceph, Sheepdog, and XtreemFS seem to keep coming up as things that might work, but... Sheepdog is too tied to KVM, XtreemFS and Ceph are still experimental. Gluster seems to stand out as mature and well supported (particularly with the RedHat acquisition), and seems to have matured a lot since we last looked. For a number of reasons (mostly rack space limits and cost) we have 4 1U machines - with 4 drives in each - no real opportunity to separate storage from processing. The machines each have 4 GigE ports - we're using 2 for external connections, and reserving 2 for server-to-server communication. All of which leads to several questions: i. Is it now reasonable to consider running Gluster and Xen on the same boxes, without hitting too much of a performance penalty? ii. Anybody out there running a small cluster along these lines? iii. Any particular suggestions, caveats, guidance, pointers to documentation, .... (particularly for a Debian environment, though it wouldn't be that hard to migrate our Dom0s. iv. Any thoughts re. phase-in and migration - i.e. how to get from 2 production nodes running Xen,DRBD,Pacemaker to 4 nodes running Gluster/Xen/<pacemaker or some other failover capability>? Or are we barking up the wrong tree entirely? Thanks very much, Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra
