I have some Very Important Data that I must ensure always exists in at least
two separate places so that a media failure will never cause a data loss.
This data happens to be DB2 (udb) logs; when a db2 client fills up a log file
it will call a script to initiate a backup of that logfile.
Then the log is backed up to a TSM server (3.7.3 on AIX sp nodes). It goes to
a storage pool on a raid group; once the backup has completed, db2 will feel
free to re-use the original logfile space on the client. So now I need to get
this data on two different tapes...one will eventually move offsite using the
DRM component.
I understand that the standard method of doing this is to take a copy of the
storage pool. Some of the data might still be on disk, but the amount of log
data we generate will quickly cause this to migrate to tape. So we do a
tape-to-tape copy and have two tapes. Fine.
Problem: In the (admittedly rare) case where we're doing the tape-to-tape copy
and a tape drive decides to eat the input tape, I could end up with ZERO copies
of one or more logfiles, a Bad Thing. So I hope to prevent this, somehow.
(BadThingThreshold=0)
Solutions proposed so far tend to include a truckload of disk so that the
migrate to tape won't have to happen, as well as various scripting solutions in
the db2 exit (force it to perform multiple archive operations) or in tsm
(on-the-fly copies, locking a db2 client, etc.).
Finally, the question: Are there no native TSM functions that can be used to
accomplish this? I've not been able to locate any in the manuals, redbooks, or
via lurking here. The question seems to also have the seasoned *SM'ers
stumped as well. As a newbie to TSM, I'm still expecting to find options in
policies that I should just be able to turn on to enable a "copy to two
different tapes during migration" option.
I have two TSM servers on the same sp cluster- are there tricks we could pull
using server-to-server configurations, etc that could provide a way to ensure
this data always has two copies? (I expect that when I get further down the
road and look at hsm functionality, I'll cross this same bridge again....we
shouldn't delete the data from the client until it's on two tapes first).
So am I missing something simple or will it take brain surgeons (or that
truckload of disk) to convince TSM to do this for us? Does anybody else have
this problem?
Thanks.... JRS.
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