A brand new XenServer pool in an external office had an interesting problem. Two hosts were added to the pool and yet they could not access two mounts on a NetApp filer.

A repair of the SR would give an error message:

There was an error while attempting to mount the NFS share.

Three other XenServer hosts had no issues.

Checked all the obvious and yet they would not repair. I considered a reload but how would that solve it?

Tried using the mount command to mount one of the shares to a directory and received an error that the server rejected the request.

I mentioned this to the administrator who owned the filer and it turns out he likes to use host lists to control access.

He added the hosts to the list and I was able to repair the SRs.