[Info-vax] Correct way to dismount shadowed volume set as late as possible?

[Matthew Wilson]

Hello,

I have a 3-node simh VAX cluster. Because there isn't a great way to do shared-system-disk clusters with simh (except netbooting satellite nodes), each node has its own system disk.

To share things like the UAF database, audit log and journal, etc., I set up a volume shadow disk between 2 of the nodes. So, for example, early in boot I check that the cluster disks are available mount with:

mount/sys/noassist dsa1: /shadow=($10$DUA1,$20$DUA1) CMN01 DISK$CMN01

Then start using the shared data in SYS$STARTUP:SYSECURITY.COM to set VMS$AUDIT_SERVER and VMS$OBJECTS, then all the other shared data in SYLOGICALS.COM.

Anyway, my problem is that when I want to shut down the whole cluster, I'm trying to figure out the right way to dismount that volume, DSA1, such that when the cluster starts up again, it doesn't say it was dismounted incorrectly and/or need to perform a long merge operation.

For my other shared shadow volumes, I just do a dismount/cluster on them before the cluster shutdown and they come back online smoothly.

But I can't just dismount DSA1 before running the @SYS:SYSTEM:SHUTDOWN command, because it obviously has data that's in use all the way through most of the shutdown process until the audit server is shut down. 

Hence my question -- what is the correct way to cleanly dismount such a shadow set that is needed all the way through audit server shutdown? Or is there an entirely different approach I should be looking at?

Thanks,
Matthew