LTO4 is rated at 120MB/s, so I'm guessing you factored in some compression
to get that up to 350MB/s.  Regardless, using the 350MB/s as a starting
point, I think it works out to 1 tape drive being able to move 11PB/yr
(just using "PB/yr" makes me cringe).  I actually came up with 4.5 tape
drive years for 50PB.

We know about the changes coming in the next version of TSM.  I've heard
that DB2 databases can be bigger, but how much bigger?  I'm guessing we'll
still need to deal with multiple instances - just not sure what order of
magnitude (10s or 100s of servers).

..Paul

At 11:20 AM 1/25/2008, Kauffman, Tom wrote:

I *may* have screwed up the math here -- but IF you can drive some number
of LTO4 drives at maximum compression and full rated write speed of 350
MB/Second for the 800GB per tape, I get 1,322 tape drive days or 3.6 tape
drive years for the first pass. Not counting mount/dismount time. 1,322
tape drives to do the backup in one day. Boy, I hope my math is off! And
I'm glad I don't have to do the recovery plan for this!

Tom Kauffman
NIBCO, Inc

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