[comp.os.vms] Volume set problems resolved

hamm@BIOVAX.RUTGERS.EDU (01/25/88)

[Summary:  never use a volume set name identical to *any* mounted volid!]

A while back I posted a question about some strange behavior after initializing
and binding a two-disk volume set.  After that, things got even stranger:
it became completely impossible to mount the primary volume;  MOUNT claimed
it was "already a member of another volume set"  *even after* repeated
re-initialization of the volume.

I gave up and called TSC, and after checking all sorts of things (could
INITIALIZE somehow be failing to write over the home block, etc.), we found
that the problem was a manifestation of a known bug:  VMS gets very confused
if you bind a volume set with a volume set name identical to another volume
id - even one on an unrelated pack.  The reason for this has something to
do with the way some part of the file system [sorry, I don't remember the
details] takes out locks - for single volumes, the lock name is derived
from the volume id, for volume sets, from the volume set name.

Since I had an existing volume with id "Users" that I was trying to split
into a two-volume set ("Users.1" and "Users.2"), I chose the volume set
name "Users" - not knowing this would cause any conflict.  The main problem
is then that the resulting error messages and behavior are quite confusing
and misleading.

Greg
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Gregory H. Hamm                           || Phone:  (201)932-4864
Director, Molecular Biology Computing Lab ||  
Waksman Institute/CABM                    || BITNET: hamm@biovax
P.O. Box 759, Rutgers University          || ARPA:   hamm@biovax.rutgers.edu
Piscataway, NJ 08854 * USA                ||
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