> Networker 6.1.4
> Solaris 8 patched current
> Sun L20 w/ 1 Quantum DLT7k current firmware
> Sun L1000 w/ 2 Quantum DLT7k current firmware
>
> Anybody know of a decent way to change the block size of a tape that was
> previously written by Networker.  We initially had the L20 connected via
> scsi-fibre router which was writing to the tapes using a 32k blocksize
> instead of the 128k normally used with Solaris (due to software problems
> that I'd rather forget).  It's now using scsi connection and we're
> finding some tapes maintain the 32k blocksize even though they get
> deleted and relabelled.
>
> I realize DLT will work with variable blocksizes, but we believe there
> is a performance decrease using the smaller blocksize.  Of course, the
> tapes could be bad (they are 2-3 years old) but I hate throwing those
> suckers into the trash. :))
>
> I was thinking that writing to a tape with tar would work, but thought
> I'd ask here in case someone else has run into this problem.

While the density written at the beginning of the tape locks the density
for the rest of the data, that's not tru for block sizes or
compression.

You should be able to test the block size issue with 'dd' and some
tests, but I can't think of any reason that existing data on the tape
would have anything to do with what block size future writes occur with.

That should be set only by the application software and the tape driver.

--
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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