I have to agree with Doug in that the mainframe can push lots of bits.
However, in the mainframe environment, I've always experienced difficulty
getting resources allocated to TSM.  When I had TSM on the mainframe, I
couldn't get more CPU even for a critical fileserver restore.  I had to go
to senior management to get more CPU _temporarily_ so I could try to repair
lovebug virus damage.  Until I did that, the restore crawled.

Out of curiosity, if you have an undersized processor, how much would it
cost to upgrade the processor as opposed to buying an AIX box to run TSM?  I
don't really know how much 390 processor upgrades cost, but I'm under the
impression that a forklift upgrade costs 3-4 million dollars, a "physically
add processors" upgrade costs a whole lot, possibly several hundred
thousand, and a "license unused existing processors" upgrade still probably
costs more than an AIX box with library.  Personally, I don't believe most
mainframe shops would be willing to upgrade their mainframe just for "a
backup application to back up open systems."

As far as badly tuned systems, how many shops are going to admit their 390
system is mistuned and correct it?  When working with just about anybody,
and mainframers are no exception, and heck, neither am I, they know what's
best and getting them to admit the errors of their ways is difficult.
Wouldn't it still be easier to purchase an AIX box for your backup system?
Also, how about the cost of process reengineering, tuning, education, or
lost man hours to tune the system?

The truth is, in the mainframe world, as long as TSM's not making money and
it doesn't have a mandate from God, it's the red headed step child.  The
mainframe already has it's own backup products, so TSM is viewed as "that
thing that backs up open systems boxes."  They have no reason to bump TSM's
resource usage, and definitely no reason to spend lots of money to
accomodate TSM performance requirements.  Of course, I'm sure there are
exceptions, but _ALL_ of the TSM people I've talked to who had experience
with TSM on the mainframe have said their TSM implementation improved in
performance immensely when migrating from 390.  My opinion is it's due to
resource constraints.

Alex Paschal
Storage Administrator
Freightliner, LLC
(503) 745-6850 phone/vmail