On 11/01/11 10:23, Aleksandar Ivanisevic wrote: > Tim Small <[email protected]> writes: > >> We don't currently use drbd in multi-master mode, instead we have a >> number of drbds per node pair, and all the VEs associated with a given >> drbd must run on the same node at the same time. >> > Thats exactly what I'm doing too. Why do you need ocfs2 then? >
We don't - we just use ext3 on DRBD. >> Another way to solve the problem would be to use similar methods to >> OCFS2 etc. (AFAIK) i.e. corosync instead of heartbeat (and use more than >> two nodes in your corosync totem ring) and set your quorum to prevent >> split-brain occurring at all. >> > I thought about that, but since drbd doesn't support more than 2 > nodes, I don't really know how that would work. > You don't have to have all machines in the cluster be drbd nodes - in the simplest case, I believe you could just have a third machine which just votes. node A runs drbd, as does node B node C doesn't, it just takes part in voting etc. If node A loses connectivity, then it shuts down it services since it has lost quorum. B+C together still have quorum, so B continues to work. If there were any late changes committed to A, they will be discarded on reconnect. ... I believe - I haven't had to implement this yet. Another possibility would be to have three nodes, all doing stuff: nodes A, B, C Each node has it's storage pool split into 4 DRBDs (or 4 sets of DRBDs if you'd prefer - there are certain advantages+disadvantages of doing it that way). drbd x1 is hosted by A and B (normally on A) drbd x2 is hosted by A and B (normally on B) drbd y1 is hosted by A and C (normally on A) drbd y2 is hosted by A and C (normally on C) drbd z1 is hosted by B and C (normally on B) drbd z2 is hosted by B and C (normally on C) Quorum is 2. If node A dies or gets isolated, then B and C take on A's work. Both B and C end up doing 50% more work than it was before node A died. HTH. Cheers, Tim. -- South East Open Source Solutions Limited Registered in England and Wales with company number 06134732. Registered Office: 2 Powell Gardens, Redhill, Surrey, RH1 1TQ VAT number: 900 6633 53 http://seoss.co.uk/ +44-(0)1273-808309 _______________________________________________ Users mailing list [email protected] https://openvz.org/mailman/listinfo/users
