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Restore a cluster when LSM is involved

Martin Begley
Occasional Advisor

Restore a cluster when LSM is involved

Tru64 Unix V5.1B-3 and Trucluster V5.1B-3


Single site cluster with cluster_root, cluster_usr and cluster_var under LSM control.

Cluster is completely lost, requiring new hardware to be wheeled in.

Assume that the new hardware is configured exactly as the old hardware and that we have a full set of backups of everything required.

What is the quickest way to restore the cluster?

I have read the various bits of documentation available such as the Trucluster Admin guide which talks about how to restore cluster_root but unfortunately doesn't mention LSM at all. Also the LSM admin guide but using volsave/volrestore explicitly ignores root, usr and var.

So how to marry it all up and restore the cluster in full from the backups? Is there a procedure anywhere for this? Or is the only solution to recreate the cluster from scratch?

We plan to have an offsite copy of the initial disk that was used to build the cluster but other than going through the clu_create and volmigrate all over again I can't easily see how to use it to recover with.

Thanks in advance.
Johan Brusche
Honored Contributor

Re: Restore a cluster when LSM is involved

Just restore cluster_root, _usr and _var as regular AdvFS filedomains in diskpartitions.

The things that would point to cluster_root
as a LSM volume are in the CNX (h-partition) of the now lost boot-disks and quorum disk.

When you recreate the replacement member bootdisks with clu_bdmgr, they will point to the newly created cluster_root partition (dsknnb)

Then after interactive booting required for booting without quorum/quorumdisk, you recreate the quorumdisk, which then in turn gets a new CNX partition pointing to the same cluster_root disk partition.

Only at the end when the new config runs with all members, you use volmigrate to bring cluster_root, _usr and _var into LSM.

See attachement for procedure.

___ Johan ./