ADSM-L

Can you have files with multiple Management Classes?

1998-03-06 09:27:16
Subject: Can you have files with multiple Management Classes?
From: John Schneider <jdschn AT IBM DOT NET>
Date: Fri, 6 Mar 1998 08:27:16 -0600
Greetings,
        I am referring to the AIX ADSM Server 2.1 PTF 15 in my question.
        I have a need to do the following:

1) Backup all the files on about a dozen AIX systems, daily
incremental.  The /,  /usr, /var etc. directories go to a management
class "backup-os", retention 3 weeks.  All other filesystems go a
management class called "backup-generic", retention.  Backups go
directly to DLT tape on a central STK9714 library on AIX server.

2) On a weekly basis (or monthly, depending on how many tapes this
takes), take a "full incremental" (in other words, all files whether
they are changed or not) of all the nodes to the same management classes
as in 1).   Same retention.  I know people say there is no reason to
every perform a "full incremental",  because ADSM still has the data.
Hogwash.  I do not wish to have my only copy of 90% of my files on one
tape, and then
find out that the one tape

3) On a weekly basis, take a "full incremental" of all the nodes to a
different set of tapes in the same DLT library, with a retention of 6
months.  This backup needs to go to a separate tapes  because the tapes
sent offsite.

4) An alternative to 2&3 would be to take a "full incremental", and
simultaneously send it to two different tape storage pools, one of which
would stay onsite, and one which would go offsite.  A "twin" or
"mirrored" backup.

        Step 1) was straightforward, and is working fine.   Each node has it's
own include/exclude file to spell out which filesystems get backed up to
which management class.  But  I am not sure how to do step 2) properly.
I could create a separate schedule for a "selective" backup, but  that
is kludgy because in the options parm you have to specify each
filesystem.  Some of the larger systems have a couple dozen filesystems,
and some get backed up while others don't, and the list changes
frequently, and it just looks like a lot of work to keep it updated and
correct.  If someone forgets to add a filesystem to the list, it doesn't
make it in to the "full" backup.
        The other way to do step 2) would be to change the management class's
backup copy group definition so that a mode of "absolute" were
specified.  I could set up a cron job on the server so that once a month
the backup copy group definition were changed, and the next incremental
backup performed for each node would back up ALL.  A subsequent cron job
run 24 hours later would change it back.  Any better ideas?

        Step 3) is even harder.  How do I back up files, and give them a
different retention period, and send them to different tapes, just one
day of the week?  The ways I could think of all have problems:

1) Code a cron script that modifies the include/exclude list on each
machine to change the management class.  The different management class
would have a backup copy group with different retention times and
storage pool.  The script could run on the day you plan to take the
backup, then get changed back the next day.  But you would have to
monitor this, and make sure it was working properly.  Each new node you
set up would have to have this same cron job set up.
        But wait!  According to pages 133-134 of the Admin Guide, the day after
you backed up the files with a 6 month retention, ADSM would rebind them
back to the old management class, and the retention would go back to 5
weeks.  So this would not work, unless I am misreading it.

2) Set up a separate policy set, and give it management classes that
have the same names as the original policy set.  The management classes
for the new policy set would specify different retention periods and
storage pool.  A cron script would activate the new policy set on the
day you want, and then switch it back the day after.  But would this
work?  The Admin Guide implies that the files would not be rebound to
the other management class because the same name exists in both policy
sets.
        But after the original policy set gets put back and a backup runs,
would the files backed up using the other policy set still have the
those values, or would they revert to the values of the new files being
backed up?  I am not clear on this.

        Is there any way to do Step 4 at all?  Other backup products (like
Legato Networker and HP Omniback) allow for what they call a "twin" or
"mirror" backup, where you back up to two tapes at once.  Then you don't
have to worry about your data disappearing because of one bad tape, and
you can send tapes offsite without worrying that you will need them
tomorrow to do a restore, etc.  This capability would be very nice.  Any
clever ways to get this done?

Sorry for the long note, and thanks in advance for any advice.  This
list is terrific.  I have been reading it for awhile now, but just
decided to post since I have not seen anything just like it go by.

Best Regards,
John Schneider

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* John D. Schneider     * Email: jdschn AT ibm DOT net * Phone: 314-349-4556 *
* Lowery Systems, Inc.  ***********************************************
* 275 Axminister        * Disclaimer: Opinions expressed here are mine*
* Fenton, MO 63026      * and mine alone.  My company is off the hook.*
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