SUMMARY: Restoring from DLT tape

From: Sam Don (
Date: Fri Feb 25 2000 - 16:53:36 CST

My post:

>I was given 200 DLT tapes backed up on a DLT4700. I'm told they were backed
>up using gnutar. When I try to restore something:
>% gnutar tf /dev/rmt/1
>gnutar: Read error on /dev/rmt/1: Not enough space
>gnutar: At beginning of tape, quitting now
>% tar tf /dev/rmt/1
>tar: tape read error
>% df -k /
>Filesystem kbytes used avail capacity Mounted on
>/dev/dsk/c0t0d0s0 1459478 1254399 59132 96% /
>I would appreciate help in getting a specific file of the tapes. I know the
>name, but I am unable to even list the contents. Is there a way of
>what was used to back the tapes?

Here are the responses:

Arthur Darren Dunham <>
That means that the tape block is bigger than the buffer
allocated by the driver. You need to read from the tape
with a bigger blocksize. Keep bumping up the 'b' flag
until it goes away..

gnutar tbf 126 /dev/rmt/1

Jeff Kennedy <>
Try this:

dd if=/dev/rmt/1 of=/tmp/testfile bs=64k count=1

This will pull the first 64k of data off of the tape and put it in /tmp/testfile. From there you can look at it and see what format it lists. ---- Danny Johnson <> don't know about gnutar, but it sounds like what tar would do when given a tape with a nonstandard blocking factor. try adding the blocking factor option with various guesses, like 20 (512-byte) blocks to start. ----- (Brett Lymn) I think you can get that message if the tape is gnuzipped. Try doing:

gnutar ztf /dev/rmt/1 ----- Michael Hocke <> Check the SCSI tape driver settings in /kernel/drv/st.conf. Make sure that you add the DLT settings to the tape-config-list. ----- Ian MacPhedran <Ian_MacPhedran@engr.USask.Ca>

A couple of things to try: 1) check the tape % tcopy /dev/rmt/1 will go through and print information about the tape contents. It may require you to use a different blocking factor with tar. (the b switch on tar) 2) make sure the drive is working. Check /var/adm/messages for warnings or errors. It may be that either the media is bad, or that your drive needs cleaning or has other problems. (Do this if you get errors from tcopy.) ---------- Jason Marshall <> Do a tcopy on the tape and it will tell you what size the "files" on the tape are. Some backup software will prepend their own proprietary stuff to the beginning of the tape (their "label" usually), so you may need to mt -f /dev/whatver fsf 1 a few times to get to the actual tar files...

The tcopy should give you sufficient information to start with... ------

It turned out that the tape wasn't tarred after all, it was backed up using dump from a SunOS machine. I restored it from a Solaris machine using 'ufsrestore -ivf /dev/rmt/0'.

Thanks to everyone. You set me on the right track!

Regards, SD ______________________________________________________ Get Your Private, Free Email at

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:14:03 CDT