Re: Does anyone shut down for system disk backup any more?

From: Wayne Sewell (wayne_at_tachysoft.com)
Date: 11/06/03 

Date: Thu, 6 Nov 2003 09:26:58 -0500

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>JF Mezei wrote:
>>
>> > >> An interesting experiment would be to find an old disk with an
>> > >> easily accessible "write protect" button on the outside. Boot up
>> > >> VMS from such a disk, get your applications going (yes, even if
>> > >> they are on a different disk), and then write protect your system
>> > >> disk.
>>
>> The audit server would get mighty mad at not being able to write its logs and
>> probably freeze the system. OPCOM woudl also get mighty mad with inability to
>> write to operator.log, and the queue manager would also complain bitterly. You
>> woudln't have a happy family :-)
>
>I've tried something similar - actually I was trying to build a minimal
>OpenVMS system on a CD - If SYSUAF.DAT is not writeable you cannot
>login. SYSUAF is also a file I have seen corrupted after a restore from
>backup done with /IGNORE=INTERLOCK.
>You always have _some_ applications on the system disk - they're put
>there when you install OpenVMS. They're just not 3-rd party. To quiesce
>the system disk sufficiently to close all files/applications you might
>as well shutdown
>
>Basic question has already been asked: If your system is critical enough
>to be up 24x365, then surely you should be _entirely_ sure of the
>quality of your backups, not 'reasonably' sure?
>Of course you could always restore a previous backup, and and one
>previous to that ... until you hit a good one, with a decreasing risk of
>failure. But it sounds inconvenient and open to error.
>

One possible compromise would be to do a standalone backup to another disk
rather than to a tape, i.e. snapshot the system disk with an image backup to
another drive of the same type. This would still require a shutdown, but the
disk-to-disk backup would be faster, so the system wouldn't be down as long.
Then you could either save the disk backup, or back *it* up to tape at your
leisure.

You could also use the *new* disk as the system disk and use the original as
the backup. This would give the advantage of defragmenting the system disk.
It's especially easy with storageworks because you can just swap the drives
after the system backup and not have to change the boot device.

It does require a spare drive, though.
===============================================================================
Wayne Sewell, Tachyon Software Consulting (281)812-0738 wayne@tachysoft.com
http://www.tachysoft.com/www/tachyon.html and wayne.html
===============================================================================
Randolph Duke (in Trading Places): "Mother always said you were greedy."
   Mortimer Duke: "She meant it as a compliment!"