We patched one server (NW65SP4A) in our cluster to SP5 and three other servers
(out of five) now have problems with their volumes. You can no longer map to
the virtual volume - only the physical one, and one server the NSS pool object
cannot be recreated. We are attempting a fix this weekend and will report back
as to our success / failure.

NTS has not heard of this problem, but my instructor (who also consults) has
heard at least one of his clients experiencing the same problem.

So if you have a clustered NW65SP4a system, you may want to hold off patching
to SP5.