Red Hat

The RO mounts are to dump the data on the LUN to LTO Tape.
The backup server is where I am mounting it RO.

Note: this is already in place on an older backup server, which we are trying to replace.
If this practice is far from best, then now is the time to change the process and get on pace with the rest of the world.
Note: This was setup prior to my taking over this process.

If it's only for backups where performance isn't an issue, why not export as NFS and just mount it on the other system?

But yeah, not wanting to mount a regular filesystem on two different network nodes is the reason we have clustered filesystems to begin with.

- Joel

First, to do this properly you need a shared file system on the LUNs. Period.

But, if you can get read-only access to the LUNs, you might be able to make it work on a non-shared if you're willing to play with fire somewhat. Just realize that because of caching you can not guarantee that the read-only host(s) will see any changes made to the file system after they're mounted on the read-only hosts.

So you will get better results if you unmount the file systems before you read from them.

But it will still be playing with fire.

FWIW I tested "export iscsi mount as read-only with nfs" and it didn't have any problems (other than that it was a little slower over NFS than iscsi, but that's predictable). My understanding is that NFS goes through the VFS so it won't care if it's local or remote.

Doesn't your backup system have some method by which to backup over the network, or your SAN to snapshot and then hand a snapshot off the the backup server?