Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
First off, do you have fencing/stonith configured? What cluster stack, if any, are you using at this time? If the VMs use the raw DRBD resource, then dual-primary alone would be fine so long as you make sure both nodes never run the VM at the same time (fencing goes a long way to ensure. If you have files backing the VMs on a file system, then yes, you would need a clustered file system like GFS2. You need dual-primary for live migration, so it's worth getting things going. However, dual-primary is not a task to be taken lightly. You will need to test you cluster stack and fencing carefully, avoid fence loops, etc. There is nothing inherently hard about dual-primary, but it is often recommended against simply because people don't take the time to do it right. And when done wrong, it's easy to blow your foot off. :) On 06/24/2013 12:13 PM, Aaron Clausen wrote: > I'm currently configuring two KVM host servers and things are going > along pretty well. I'm story KVM images directly to the drbd devices > in raw format, and it's working very well with tolerable overhead. > > One thing I am wondering, however, is whether I can safely switch from > primary/secondary mode to dual primary. I know in most cases you're > supposed to have a shared cluster file system, but primarily my > interest here is in quickly migrating from server to the other. > Removing "drbdadm primary"/"drbdadm secondary" would make things a bit > easier. As it stands, only one server is going to be accessing the > drbd device at a time (firing up two guests with the same MACs, > network configs and the like would be pretty ugly all on its own). > > Or is it simply safer to continue running in primary/secondary mode? > > -- > Aaron Clausen > mightymartianca at gmail.com > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?