topic Re: stape driver & Tape Write Buffering ? in Operating System - HP-UX

stape driver & Tape Write Buffering ?

Edward Wynn — Fri, 05 Jan 2001 11:37:08 GMT

Hi,

I have been having problems with cpio trying to backup to a Sony SDT-11000 (DDS4) from HP-UX 11.

This is a new HP Machine and DAT drive and I am using new tapes (although I have tried used ones), the problem is that I can write a small amount of data to the tape, like this:

find /home/eddiew -print |cpio -ocv >/dev/rmt/0m

and this works without problem. However if I try to backup:

find /home /etc -print | cpio -ocv >/dev/rmt/0m

then the backup fails with:

write failed: I/O error
Unexpected write error (errno: 5).
Archive aborted.

As I can write small amounts of data to the tape I think that this proves the tape/hardware are OK and that this problem is something to do with buffering - can anyone suggest any solutions and or patches I may need to install.

Many thanks in advance, Eddie

Re: stape driver & Tape Write Buffering ?

Alexander M. Ermes — Fri, 05 Jan 2001 11:41:54 GMT

Hi there.
Perhaps you can use this little script:

#!/sbin/sh
# ============================================================================
# This script will cpio out all database files to the device
# given as Parameter 1
# ============================================================================
#
set -x
today_=`date +'%y-%m-%d'`; export today_
#
LOG1=/usr/tmp/cpio_${today_}.1st; export LOG1
#
PATH=$PATH:/usr/local/bin
export PATH
exec > /usr/tmp/cpio_${today_}.log 2>&1
#
#
find / /u001/var /u004/alex/copy /u010/opt -xdev -fsonly hfs -depth -print | cpio -ocBv > /dev/rmt/1m 2>> ${LOG1} &
first_cpio=$!; export first_cpio

#
wait $first_cpio

if test $? -ne 0; then
echo "Full Offline Backup did not complete successfully!"
fi
echo "Time is: `/bin/date`"
echo "Time is: `/bin/date`"
echo "Time is: `/bin/date`" >> ${LOG1}

Rgds
Alexander M. Ermes

Re: stape driver & Tape Write Buffering ?

Bruce Laughlin — Wed, 10 Jan 2001 19:43:13 GMT

Hi Edward,

I don't have a DDS4 tape drive, so unfortunately, I can't play around with this.

As far as patches, the following mention DDS4 support:
PHKL_22856 SCSI Tape (stape) cumulative
PHKL_22941 SCSI IO Subsystem Cumulative Patch

You may want to look into these patches, and their dependencies.

Also, with regards to the fbackup behavior you were describing, the last time I checked, fbackup does not support DDS4. It seems to me, however, you can use the tape drive with fbackup as long as you:

1) have the patches I mentioned above, as well as the latest fbackup patch, PHCO_19732
2) and use 120M tapes instead of 125M.

Granted, this puts the drive into DDS3 mode, but it's better than using it as a paper weight :-)

Hope this helps,
Bruce Laughlin