We're in the process of implementing SAP/R3 and I've been tagged with
answering the question of how many tape drives do we need for backup/recovery.

The environment:

SP2 frame, with six processor high node for DB server, wide node for the
ADSM server, and the SP-switch for the network. We project a final size of
about 100 GB for the SAP database, and an initial size around 70 GB. We
currently have one (1) 3590-B11 with ACF as our tape storage.

First of all, the database will be mirrored (its on SSA disk) such that
loss of a disk drive or a disk adapter will not cause database failure. The
DB server will be part of an HACMP cluster, so we shouldn't run into
problems here either.

But -- I've heard reports that ADSM runs roughly 6 GB per hour per tape
drive (and our experience tends to back this up). Can I hang my hat on this
number? Can anyone pass me an absolute maximum restore rate (observed, not
theoretical)? We're trying to decide wheter we want five or six tape units,
or lots of disk in an intermediate storage pool. I'm not so much concerned
about backup speed, but instead tape copy and restore performance.

I don't anticipate many restores for hardware reasons - I'm concerned,
though, about the possible requirements to restore after failed software
updates or inappropriate database changes (any war stories out there from
other SAP sites?).

TIA

Tom Kauffman
Sr. Technical Advisor
NIBCO, Inc.

namffuak AT nibco DOT com