tape to tape copy --> duplicate a cpio archive

[Denver Osborn]

Looking for ideas...

What's a good method to duplicate a cpio tape using a tape to tape copy?

My source and copy tape are located on different boxes in the same network. Both DDS-3 drives. I've already tried using dd piped throuh ssh to the copy host, but it failed when I list the tape contents... get "out of synch" errors.

Here are the cmds from the "failed" attempt;

dd if=$SRCTAPE bs=5120 |ssh -l root $CPHOST "/usr/bin/dd of=$CPTAPE bs=5120"

The dd completes w/out error, but cpio to list the contents fails on "out of synch"... using -R gets a little more to the list, but ultimately fails. I'm assuming dd won't be my answer.

Any thoughts on the best (safest/fastest) method to do this is?

Thanks!
-denver

[Elmar P. Kolkman]

The reason it doesn't work is probably linked to the block size used. Are you sure the blocksize is 5K ?
I've done this in the past, with remsh instead of ssh, and it worked fine. Even with ascii to ebcdic conversions etc. But the bs is really important!

[Denver Osborn]

The archive was created using cpio's -B option, so I set the dd bs = 5120 bytes to match.

-denver

[T G Manikandan]

Use dd

tape1 to disk
#dd if=/dev/rmt/?? of=/tmp/file bs=5120

disk to tape2
#dd if=/tmp/file of=/dev/rmt/?? bs=5120

This should do the work for you

[Denver Osborn]

The tape to disk, disk to tape won't work for me... don't have the additional space sitting around. :)

I'm also looking to avoid running a 2nd cpio to create another tape from the filesystem, the original took about 14 hours to complete. this is why I looked to dd 1st to do the tape-to-tape via network.

-denver

[Denver Osborn]

if anyone cares... may have solved my problem.

Had to specify both ibs and obs with dd. I figured simply "bs=5120" was supposed to set both input and output bs... either way, setting ibs=5120 and obs=5120 seems to be doing it.

-denver