Mitch Collinsworth wrote:
>
>
>OK, forget Legato. I just found out it costs a fortune
>(read: as much as the new DLT tape changer we're buying).
We wrote extensions to the old dk backup package (originally from
Tektronics, placed in the public domain) to handle our afs cell (it
also does all our unix backups). Basically, we grok volinfo output
and compare it to a log of recent backups to develop a list of volumes
needing backup. A perl script then develops a daily backup list for
each tape. A find utility groks the logs to determine the location of
each volume on tape for restores. Unfortunately, you can't do a
variation of a vos restore to just get a table of contents for the
dump, so an index by file isn't possible. Maybe an afs 3.5 enhancement?
We currently use a two week epoch cycle, and run daily level ones. In
the past we did weekly level ones and daily incs, but with the number
of volumes we oversee, we decided that the wastage of tape was worth
it to decrease the worst-case number of restore tapes from 8 (epoch +
level1 + 6 incs) to 2 (epoch + level1). (In our environment, our incs
run ~15% of the total volume space. YMMV.) This decision was
validated last fall when we lost 2 8 Gig partitions at 4 PM one Sunday
afternoon and had all the restores completed (from 18 tapes) by 6AM
the next morning.
In order to get reasonable data rates to tape, we multiplex several
dump streams on each tape (as opposed to simply contatenating dumps
one after another). Some purchased software also allows you to do
this, and your dumps will take much longer if your backup system
can't. Beware if you go down this path, that your vos dumps can get
starved by the number of threads your volserver can handle (we run our
volserver with '-p 16'). Our scheduler and backup utility work
together to keep the number of simultaneous vos dumps per server low.
--
David Thompson <[EMAIL PROTECTED]>
Associate Researcher Department of Computer Science
University of Wisconsin-Madison http://www.cs.wisc.edu/~thomas
1210 West Dayton Street Phone: (608)-262-1017
Madison, WI 53706-1685 Fax: (608)-262-6626
--
