>I want to maintain just one tape storage pool and one copy pool.  Can
>disk backup pool, disk archive pool, and disk space management pool all
>migrate to the same tape pool?  What are the pros and cons?  My server and
>clients are both running on AIX 4.1.4.  The tape device is a 3494 Magstar 
>library
>system with two 3590 drives.
>
>Thanks in advance,
> Eliza Lau

We are similarly configured, with a 3494 and 3590 drives.
Your question is basically addressed by the ADSM HSM "redbook" (SG24-4361),
section 3.1.2.  IBM says you can go either way.  I chose to go with a common
storage pool arrangement for backup, archive, and spmgt, with a primary disk
stgpool and secondary 3590.  I have run into one problem, getting errors:

07/16/96   11:20:07      ANR9999D afcreate.c(867): Unexpected result code (159)
                          from ssClone.
07/16/96   11:20:07      ANR0530W Transaction failed for session 3 for node ACS5
                          (AIX) - internal server error detected.

when trying to perform an incremental backup of the HSM data.  IBM Support is
working this problem: Code 159 indicates Volume Conflict, as migration and
backup are trying to use the same volume.  This should not be a problem,
and so it is being worked as a defect.  (This is with the latest client and
server code.)
    The big downside to segregating storage pools is in having to carve up
your 3494 into separate scratch pools, which is rather undesirable, as one
wants to have scratches available to fill any and all needs.
          Richard Sims, Boston University OIT