Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 10/30/11 20:34, Trey Dockendorf wrote: > > > Hi, > > a cluster software like Pacemaker could serve your purpose very > well. Do incorporate STONITH though, as you will need dual primary DRBD. > Mind you Pacemaker is NOT easy, requires a lot of study and reading. > > Share image files could be done with OCFS2 for example (or any > clustering file system). You then need to create a Pacemaker > resource handling this. Personally I never used OCFS2, but there are > lots of eaxmples around. > > HTH, > > B. > > Looking at the man page for STONITH I'm not sure I understand how to > incorporate that into this particular situation. When I put DRBD in > dual primary that will be only for the purpose of live migration, but I > don't really plan to use live migrations at first for failover. My > initial purpose is for maintenance, to allow me to reboot one node > (after kernel update) and move all the VMs to the other node. Once I've > got all that working smoothly then I'd move to having it serve a > failover function. If you don't need live migration, you can safely forget about dual primary. It is actually even better since it is (or rather can be) a can or worms. No reason to go for OCFS2 either, unless you want shared storage for your config files (though NFS might serve that purpose too). LVM with a regular file system is fine, very good for backup. But do keep in mind that a master/slave system (or primary/secondary DRBD) will in no way allow you to live migrate. You can however always add it later, though converting from ext4 to OCFS2 probably will require backup and restore. > Would OCFS2 be used in conjunction with DRBD? From a few articles I've > found, I thought that what could be done is create a LVM that stores all > the qcow2 images (part of my current deployment already) named > lv_vmstore. Since I'm running CentOS 6 I've been formatting that ext4. > Would I not then use DRBD to replicate lv_vmstore across both nodes? > > One catch to all this I think I forgot to include in my initial email is > I have no shared storage. I only have 2 physical hosts with > approximately 1TB isolated for lv_vmstore. Someday once budgets allow I > may have a SAN, but for now I am trying to facilitate live migration > without one. DRBD is a technology that would allow you to be without a SAN. But do you or don't you need live migration (as you now mention you do)? > Thanks > - Trey B.