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Re: [Linux-cluster] virtual machine failover with gfs

On Jun 25, 2008, at 4:41 PM, Joe Royall wrote:
Why not use lvm backed vms, 1 per vm, share the entire partition with all the lvms via ISCSI to each dom0 and run clvm on the dom0s. The lvms do not need to be mounted in dom0. You can then use RHCS to failover vms between dom0s. Consider putting all the vms on a single node into a single resource group and only allow 1 group to operate on a single node. You can then configure N+1 redundancy.
Joe Royall
Red Hat Certified Architect

We already have all of the nodes attached to a san vi fibre channel, so I would rather not just provide storage from the san through another box as an iscsi target to these 4. It seems like it would add a layer of complexity and performance bottlenecking.

It seems like I could do the first half of what you talk about, instead of making a gfs filesystem in the clvm lv and using files there for the vm backends, I could make multiple lvs in the clvm vg and use one for each vm. This gets around using gfs at all, and I could just have a resource per vm for it's lv. I am not sure how I would specify this in cluster.conf so that the lv would get mounted on the proper node that was going to run a vm. From what I have read, a <vm> element can't be a child of a <service> element and there doesn't seem to be any other way to define a relationship between the two.

Are all resources in a cluster only ever on one node at a time, or is there a way to specify that a resource should be on more than one or all nodes as they join a cluster?

I looked that the nfscookbook available from Red Hat and it seemed to describe a similar problem, I could create 4 services for the same gfs filesystem and have each in a failover domain for each node. At this point this seems like not even a good problem to use gfs for, I got the idea from that Red Hat Magazine article that seemed to be describing the very problem I am trying to solve.

matt whiteley <whiteley pdx edu>

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