Paul...in response to your questions below....

Yes, ADSM does its own memory caching of the
database and recovery log.
Parameters in the server options file control this (I think
they're BUFPOOLSIZE and LOGPOOLSIZE).  I don't believe we don't
do any memory caching to the storage pools and it
probably doesn't make any sense to since caching
only benefits with multiple hits to the same data....backups
going to storage pools will probably never be recovered
within a few seconds...thus caching will be a wasted effort.  We
do however, cache data within disk storage pools when we migrate
data to tape storage pools.  This makes sense because it utilizes
disk storage volumes for caching until the space is needed (otherwise
the space would just be vacant and not utilized).

You were probably recommended to use JFS files because ADSM
development found some AIX bugs which caused problems when
trying to recover logical volumes.  I believe those have been
fixed but I think we're still a little leary.  Again, in terms
of performance there seems to be no difference of logical volumes
over JFS files.

For total throughput during nightly backups there are a number
of general performance items to look at depending on your server
(eg, multiple paths to the server, etc.).  As far as
with your storage pool setup, the only thing I would recommend
is to make sure you have multiple devices within your disk storage
pool so that data from multiple clients can be writing to the
same storage pool simultaneously.

Greg Tevis

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>Can you tell us if ADSM does its own caching for database I/O?  If so,
>then I would think that the JFS caching would then be superfluous overhead.
>If ADSM does NOT do its own caching, then the JFS caching would be useful.
>
>Same question for disk storage pool I/O.  Does ADSM cache in memory for
>this?
>
>Same question for log volume disk I/O.  Does ADSM cache in memory for
>this?
>
>We actually started out using raw logical volumes, and then switched
>over to JFS files at the recommendation of an IBMer many months ago.
>We haven't done any careful analysis of whether this helped us or not, but
>the question has been bothering me a bit ever since the beginning.
>
>We are most concerned with ADSM performance during nightly backups.
>And really, we are more concerned with data throughput than with the
>performance of any one system.  Do you have any recommendation for this
>particular emphasis?
>
>Thanks.
>..Paul