Re: Tape Audit vs. Delete

Note that DELETE volser DISCARDDATA=YES will also discard the data from the
copy storage pool.  You have to restore the volume before you can delete it,
or you lose all.

Rich


At 02:28 PM 4/7/99 -0400, you wrote:
>At 12:09 PM 4/7/99 -0400, you wrote:
>>If I have a tape that is no longer readable, is there any difference between
>>doing
>>  AUDIT FIX=YES or doing
>>  DELETE volser DISCARDDATA=YES
>>???
>
>YES.  They are different.
>
>An audit will only delete those files on the tape that are unreadable.  A
>delete volser will delete all the files on the tape, regardless of whether
>they are readable or not.
>
>Note that the audit process can take quite a while (days) to audit a tape
>with a bad spot on it.  I've got an audit going now that's been running for
>many days.  The logic (at least for DLT tapes, dunno about others) is that
>if/when audit encounters a file that it cannot read (because of a bad spot
>on the tape), it will reposition the tape (LOCATE) to the next file.  In
>order to do this (on DLT) the tape must first be rewound, and then a LOCATE
>(or SEEK) is done to the tape block fo the next file.  One other thing I am
>noticing is that the timeout for the READ that eventually fails can take
>hours.  So - each file that cannot be read can take hours to process.  Not
>a pretty site if the bad spot on tape contains many files.  If you've got
>small files on the bad spot, this makes things take longer.
>
>The above description is based on empirical evidence, and some
>conversations I had with one of the developers a couple of years ago in
>response to an APAR I had opened about this.  Audit used to simply give up
>after encountering the first bad file, and mark the rest of the files on
>tape as bad.  It no longer does this.  At least for DLT.
>
>If you have copy storage pools, then you can just get the files off of
>those tapes.
>
>..Paul
>
>

Richard C. Dempsey                 email: dempsey AT kodak DOT com
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