Yes, in my experience, a frozen tape is very rarely due to an actual I/O error writing data to the tape. It's usually due to robotic inventory inconsistencies, write protect, or something similar which really has nothing to do with the integrity of the tape itself.
And yes, even if you do get real I/O errors writing to a tape, it doesn't mean all of the data already written to the tape is unrecoverable. If there is one bad bit on the tape, all the other fragments that don't cross the bad part of the tape should still be completely fine to use for recovery. As others have said, look through the logs for the actual error that is being thrown. Cheers, Dean On Fri, Sep 4, 2009 at 12:26 AM, <[email protected]> wrote: > 1) if you have netbackup set up to overwrite a tape that has other > types of data on it, it will use it and not freeze it. Depend on what > your settings are > 2) yes it does not like to over write catalogs that is why your cat > tapes are in a different pool and should always return to that pool so > you don't have this issue > 3) again yes > > But you missed one > 4) if the tape is write protected and it picks it for a backup, loads it > in the drive and sees that it is write protected it will freeze the > tape. This does not mean that the tape is bad. This happens to me some > times if I am doing a restore and it is still running when I go home for > the night. The restore could finish and the backups could the choose it > for a restore. When I remember this I will try to suspend the tape > before I go home to it will not choose it and freeze it. So whenever I > do get notice of a frozen tape I check to see if it was write protected > for a restore before I tag the tape as bad. > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Heathe > Kyle Yeakley > Sent: Wednesday, September 02, 2009 8:25 AM > To: [email protected] > Subject: [Veritas-bu] Frozen Tapes > > Hello, I had a question on Frozen media. > > First, am I correct in saying that the criteria NetBackup uses to > determine if it should freeze a tape is: > > 1) NetBackup detects Non-NetBackup data format (So data was written > using straight Unix tar, pax, cpio, or a non-NetBackup commercial app > like Tivoli or Networker) > > 2) NetBackup detects that there is NetBackup data on the tape, but it's > catalog data, and so it freezes the tape to ensure that the catalog > files aren't overwritten. > > 3) NetBackup tried to read/write to the tape and experienced more that 3 > > read/write errors within a 12 hour span of time. > > Assuming I'm correct so far, then is the proper method of > troubleshooting Frozen media to: > > 1) Ensure there isn't some catalog data on the tape. > > 2) Ensure that the tapes aren't from some other commercial backup > product environment's tape pool (for those of you running multiple > commercial backup applications at a single site). > > 3) Make sure your tape drives have been cleaned recently. > > 4) Use bpmedia -m <media id> -unfreeze to unfreeze the tape(s), make a > note of the tape you're unfreezing, and leave it in the scratch pool to > see if it gets used for tonight's backups. > > Now for my question: Assuming I was correct on my selection criteria and > > my troubleshooting steps, am I correct in saying that if I came in > tomorrow and that media from step 4 was frozen a second time, that it > indicates that the media is more than likely defective? Is there any > other troubleshooting steps anyone would care to add? > > Thanks. > > - Heathe Kyle Yeakley > _______________________________________________ > Veritas-bu maillist - [email protected] > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu > > > _______________________________________________ > Veritas-bu maillist - [email protected] > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu >
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