"tape reset" command sometimes fails on DLT tape

[MonocleMike]

I'm running 5.0.6 on a Compaq ML370 with DLT SCSI tape.
My overnight backup script run from cron starts as follows:
"
T=/u/phswin/nightlog.log
echo "`date` Starting tape backup" >>$T
tape reset 2>>$T
sleep 30
echo "`date` tape rewind" >>$T
tape rewind 2>>$T
sleep 30
tape status >> $T 2>>$T
"
and sometimes the start of the log reads as follows:
"
11:00:01 PM Mon 10 Mar 2003 GMT Starting tape backup
tape: can't open '/dev/xct0': Device busy
11:00:32 PM Mon 10 Mar 2003 GMT tape rewind
status : ready beginning-of-tape
soft errors : 0
hard errors : 0
underruns : 0
"
and on other nights it works without error. Either way it runs correctly after the tape reset command.
We have also noticed when loading the tape that sometimes it takes a very long time to initialise the tape and settle down with steady lights but we have not been able to check whether there is a correlation between that and the reset command subsequently failing. The sleep commands probably are not needed but are there togive it more of a chance!
Any ideas anyone?

 

[apeasecpc]

It sounds to me like you may be using different sized tapes. I would expect a longer tape to take longer to retension when it is inserted, and the sleep 30 command may not wait long enough for the process to complete.

First, verify that you are using the same sized tape each night. If that doesn't resolve the problem try increasing the sleep time in the script.

 

[MonocleMike]

Thank you for the suggestion BUT all the tapes are identical AND the tape is inserted at the end of the normal working day - say 17:00 - and the script doesn't run until 23:00.
I wonder whether the command doesn't work properly on modern Compaq SCSI DLT drives and I should just leave it out! It is there because this is an old script that was used for years on an HP with DAT tapes.