Tom,

Sorry, I don't have any restore rates to give you. Under normal conditions, 
backing up across an SP switch, we're getting up to 16GB per hour. I just want 
to pass on some capacity planning tips. You won't be able to go too far with 
the ACF and one drive. Tape reclamation is one reason. There isn't even an 8mm 
to move data to, so you'll be going through a lot of tapes. Assuming that you 
decide on a 3494 robotic library and 2 or more 3590s, check the number of open 
slots you have left on the wide node. We had to move our ADSM server to a high 
node so we could run 4 drives on separate SCSI cards. With 4 drives, we can do 
reclamation or offsite copies concurrently with our backups (or reclamation and 
offsites concurrently). Those are just a few things to look at.

I hope that helps.

Jim Bootz
bootz AT adc DOT com

>
> 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
>