Paul - Don't feel bad about knocking me about the head,
as it's sometimes warranted and can do some good. :-)
I won't use age as an excuse. Now let me try to provide a better answer...
As for 3590E speed specifically: When getting a new and unfamiliar device in
the shop, I advocate first getting some in-this-shop benchmark numbers before
committing it to production, and stress-testing it to see what it can and
cannot do. (We once encountered the very interesting case of a SCSI disk set
which would lock up under intense activity. Only when we confronted the
offbeat vendor about this, they revealed that in their engineering they were
not adhering strictly to SCSI standards but instead tweaking their design
according to what they found they could "get away with" under the operating
systems they tested with.) In general it's best to get numbers with your
current adapters, microcode, device drivers, and operating system level rather
than depend upon vendor specs.
If you're running Unix, I'd recommend taking one such 3590E drive away from
TSM and running the 'dd' command against it, feeding in either a very large
file or /dev/zero, where the latter will very rapidly fill the tape with
binary zeros, with no file system activity. (Or you could write a short
program to write a buffer until the tape fills, or use the 'tapeutil' command
to drive it.) Then do the reverse, reading the tape via 'dd' and sending the
output to /dev/null. This will give you essentially "ultimate" values for
your configuration.
Within TSM I would create a large file in a new file system. (A "sparse" file
might be an idea, to save space and yet cause its reader to read what it will
perceive to be much larger file than it is physically.) Use the client to
back it up directly to tape, collocated by file system to get it on its own,
fresh tape, and get timings. Now use Move Data and time how long it takes to
copy that tape-isolated file tape-to-tape within the server. You could also
try a migration to get comparative timings on that. That kind of thing.
This should provide useful figures for you, inside and outside the
application. Hope that's a more useful answer.
Richard
