need dump opts for DLT2000 on 10.20

[Matt Livingston]

G'day all,

I am trying to configure a /usr/bin/dump command line to run on a machine called host1 (hp-ux 10.20), dumping another machine's (host2 hp-ux 11.00) filesystems to host1's tape drive, which is a DLT2000. host1 was previously backing up 17GB to this same drive via OmniBack (A.02.55) using that product's Standalone DLT driver.

The problem I am having is that I am unable to get more than about 13 GB dumped to the DLTIII media before dump detects end of tape. I'm sure I should be able to get more than that onto a single tape.

I suspect I may have something wrong in the options. The command I am using works beautifully on other 10.20 machines with DLT4000 and DLT7000 drives, but with the DLT2000, it silently closes the tape device (presumably 13000 feet into the tape). Increasing the value of the 'f' parameter on the dump command (to 4000000 !) merely means that a physical end of tape is reached first.

Here's my command line. What am I doing wrong?

# remsh host2 "dump-wrapper 0bdsf 126 54000 13000 host1:/dev/rmt/1mnb /data"

dump-wrapper is a very basic script to call dump or vxdump depending on filesystem type. It has worked well wherever I have used it before, so I doubt that it is at fault, but here it is anyway.

#!/usr/bin/sh
# dump-wrapper: Call dump or vxdump as needed
DUMP_ARGS=$*
TARGET_FS=`/usr/bin/echo $DUMP_ARGS | /usr/bin/awk '{last=NF;print $last }'`
FS_DEVICE=`/usr/bin/bdf $TARGET_FS|/usr/bin/tail -1|/usr/bin/awk '{print $1}'`
FS_TYPE=`/usr/bin/grep "$FS_DEVICE " /etc/fstab|/usr/bin/awk '{print $3}'`
case $FS_TYPE in
hfs) DUMP_COMMAND="/usr/sbin/dump";;
vxfs) DUMP_COMMAND="/usr/sbin/vxdump";;
*) /usr/bin/echo "$FS_TYPE has no known matching dump command.\n$TARGET_FS not dumped."
exit;;
esac
/usr/bin/echo "Now dumping $TARGET_FS using $DUMP_COMMAND..."
$DUMP_COMMAND $DUMP_ARGS

[Stefan Farrelly]

dump is terrible at calculating the amount of data it can fit into a single tape unless you get a myriad of options on tape length, density, etc absolutely correct.

To workaround this pipe dump into dd before writing to tape; eg. dump 0f - /tmp | dd of=/dev/rmt/0m bs=64k
This will allow you to write up to the maximum amount on the tape.

[Matt Livingston]

Thanks Stefan,

I now suspect a dodgy tape, or that it was not at file 0 at the start of the backup. The command which failed on one tape has worked on another.

I'll probably end up taking your suggestion on board, anyway.