Folks,  
        I am finally getting replacement hardware for my TSM servers. I
won't bore anyone with details, but in brief they are IBM p550 Quad-CPU
hosts.

        The other part of this upgrade is to go from SSA disks to a SAN
(EMC CX3-80, in this case). I have followed all the threads about how
people are "plaid"ing LUNs to get good performance and I am thinking
about trying it.

        The issue I have is that the storage folks are asking me to
characterize the IOPS and sizes of I/Os that the TSM server is doing so
they can figure out optimum stripe size and the such. The current
systems are on AIX5.2,RS/6000 hosts. I can see various things through
"topas", "nmon" and "iostat", but it's really not telling me the size of
the I/Os that are going to the DB, the storage pools or the tape drives.


        Perhaps there will be differences between installations, but
does TSM have a default I/O size? Can anyone share the enlighten me on
what the I/O sizes are, or how I can find out?

        Thanks,
        Ben