Hi Allen,
What you recall is correct.
MVS doesn't understand open file systems, and a non-MVS OS doesn't
understand MVS filesystems.
You can't use TSM to do your mainframe backups in any way (except for
the O/E component of MVS, which is a unix-style filesystem.
If you use mainframe software to backup O/E, you get a backup of an HFS
filesystem in 1 big clump. The TSM client for O/E can read inside the
HFS and back it up by directory/file.)
Offsites for the mainframe are just as they've always been:
* Some sites rotate older generations offsite, keep newer
generations onsite
* Some sites have the software (like DFHSM) do it the TSM way,
with a copy onsite and another copy offsite generated by the same
software.
* Sites with $$$ to work with are starting to use replication
tecnology to fling the bits cross country instead of using traditional
CTAM (Chevy Truck Access Method) to move the tapes physically.
VTS (I assume you really mean VTS, not generic VTLs) in general is not a
good fit for mainframe (or TSM) backups, because the 3494/3584 VTS was
designed to work with small volumes, and the backup software (either
DFHSM or TSM) wants to write big, full volumes. Although it can be made
to work, you get better performance out of raw tape than a VTS for
backup.
If you need more info on that issue, let me know...
Wanda
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Allen S. Rout
Sent: Monday, May 01, 2006 1:29 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Mainframe backups...
Greetings, all.
I've gotten a request to update my opinions on ways that TSM can help
the mainframe do backups. What I'm recalling from previous
discussions we've had here is that the MVS filesystem structure, and
the files theron, are sufficiently different from the heirarchical
structures of byte streams we're accustomed to, that much of TSM is
inapplicable to MVS data.
So, for those of you in a mixed-mode shop, is TSM anywhere in the
backup picture for your mainframe data? How are you doing offsites
for the mainframe? Is it a VTS thing, or are there other methods you
prefer?
- Allen S. Rout
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