ADSM-L

Re: volume usage

1996-02-20 14:50:44
Subject: Re: volume usage
From: Dave Crockett <crockett AT VNET.IBM DOT COM>
Date: Tue, 20 Feb 1996 12:50:44 MST
Bill writes:
> I don't do it anymore on the primary becasue I switched over to
> collocation. I do it on the copypool tapes because they are not
> collocated and are offsite.  When that pool is 95% full, I will start
> rolling it over with 'move data' commands like I used to on the
> primary.

I just wanted to point out the ramifications of running with your
primary storage pool with collocation and your copy storage pools
without collocation (which you have probably already considered).
The trade off is reducing the number of tapes and  time during backup
stgpool versus a potentially very lengthy restore in  the event of a
disaster.

As you are doing incremental backups of your storage pool data using the
BACKUP STG command, overtime the data for a given client will be spread
over many volumes in the copy storage pool.  After a disaster, the
offsite copy storage pool volumes can be brought back onsite and clients
can immediately start restoring their data.  This of course can involve
many tape mounts for each client since the copy storage pool isn't
collocated.

You could instead restore your primary storage pools first, but this
could involve even more tape mounts if you are restoring directly back
into a collocated pool.  It will grab a given copy storage pool volume
and then collocate the data for that volume, involving many mounts.
Then it will do the same with the next volume.

Probably the best method to use in this mixed collocation environment is
to restore the storage pool data into a very large disk pool and then
let migration move the data off to the collocated tape pool in a more
orderly way.

Dave Crockett - ADSM development
<Prev in Thread] Current Thread [Next in Thread>