Why shadow copy ?

[Wim Van den Wyngaert]

Cluster of 2 * 4000 with a HSZ50 controller.
OpenVMS 6.2 1H3.

I shut node 1, 20 seconds later node 2.
Both ended by dismounting the disks without any files open (except system disk).

I rebooted them with 2 seconds between the 2 b commands.

All disks are in shadow merge.

Why ?

Wim

[Uwe Zessin]

Any pagefile or installed images on the disks?

There have been some, well, 'holes' in the dismount code, if I recall correctly.

[Wim Van den Wyngaert]

Uwe,

Pagefile is open but not on ALL disks.
Where the dismounts to close to one another ?

Wim

[Uwe Zessin]

If the code worked properly, then there should not be any race conditions.

Do you use any host-based RAID software except volume shadowing
(the striping driver for example)?

[Volker Halle]

Wim,

if the transaction count (SHOW DEV D) on the disk is 1, it should dismount cleanly. You could add an appropriate SHOW DEV D command into SHUTDOWN.COM before the final DISMOUNT command. I once even added a SHOW DEV/FILES disk, IF F$GETDVI(disk,"TRANSCNT") .GT. 1 - you need to watch/capture the output of SHUTDOWN.COM to see, which disks would still have open files.

You cannot cleanly dismount a disk with a page-/swapfile installed. DISMOUNT is a synchronous command, so they can't be 'too close to one another'.

The HSZ50 is connected to a shared SCSI bus, so the disks are 'local' to each system, right ?

Volker.

[Robert_Boyd]

I would have to say that I often had that kind of experience with V6.2 systems.

Later versions 7.2 and following have been much better. I would say for V6.2 that you need to allow at least 1 minute between them, possibly more. Or you could do the cluster shutdown -- but that always seemed to take forever for the final handshakes to complete.

Robert

[Wim Van den Wyngaert]

Uwe : no host based raid.

Volker : I do capture a show dev/fi of every disk. Nothing is open except indexf. Don't do a sh dev d yet. Yes, shared scsi.

Wim

[Volker Halle]

Wim,

can you test this in the running system ? Try a DISM DSAx: on one of the shadowsets from both systems and then mount the shadowset again with the same command as in SYSTARTUP_VMS.COM - what happens ?

Volker.

[Wim Van den Wyngaert]

Volker,

I have to wait until the merge is finished.

Wim

[Wim Van den Wyngaert]

Volker,

Tried to do a dismount dsa14 a few seconds after the merge completed. The command hangs and is not reacting to control_y.
After a few minutes : the device dsa14 is in mntverifytimeout but normally accessable from the other node. Dismount still active (or better nonactive).

Wim