Hey- sounds like your talking with marketing.

     I've got 8 3490E's in my 3494 and haven't seen any degredation since
     the time I had only two.

     If your 3590's will be scsi attached, please forward all 3590
     performance numbers to the nearest junk bin.  During all of our
     testing, scsi attached 3590's beat scsi 3490E by no more than 10%.

     No bang for the $.  I was getting 4 meg/sec on 3590 vs 2.8 on 3490e.

     BTW the 3490/3590 test was on standalone drives, each on a different
     scsi bus, using sysback to backup raw devices.

     ;(


______________________________ Reply Separator _________________________________
Subject: How many 3590's can ADSM support?
Author:  "Coleman; Barbara - WWH" <colemba AT WITCO DOT COM> at ~Internet
Date:    9/11/97 12:12 PM


I am thinking about getting 8 3590's in a 3494 library.
 Currently we are running 1 ADSM server on a wide node in an SP complex.

An IBM rep. has told us that a single ADSM database can only drive up to 4
tape units concurrently before performance degradation.  They also said that
ADSM on AIX can only support the backup of 50GB an hour.

IBM has recommended that we have at least 2 ADSM servers on 2 SP nodes. Each
ADSM server would then be connected to 4 drives in the 3494. This is not a
realistic solution for us.
It also doesn't seem possible that it really is supposed to work like this.

Our requirements are that we back up a 200GB database in 2 hours - (backup
at a rate of 100GB/hr.) And, we want to be able to run all 8 tape units at
one time with only 1 ADSM server.  Some tape units will be backing up other
platforms at the same time that we are backing up the 200BG database.

Does anyone have information about what ADSM will support?
Is anyone using ADSM on AIX with more than 4 tape units? If so, what kind of
performance are you seeing?
Is anyone backing up 100GB/hr or more? How?

 -Barbara Coleman
E-MAIL:  colemba AT witco DOT com