SUMMARY: Remote Tape drive backup

Date: Mon Apr 01 1996 - 11:07:43 CST

Recently, I posted a question to the Sun Managers list about how to
perform a remote backup of files on a machine. I've received a few
replies to my post and am very grateful for the help these people
offered. I have not been able to do what I want, but I do have a
partial solution.

One of the respondents to my question suggested providing more details
about my problem and a clearer explanation of what I wanted to
accomplish. Rather than include the original question, I've included
an updated and hopefully more clear definition of the problem.

I have access to two machines, machine1 and machine2. Machine1 is an
IBM RISC 6000 running AIX v3.2.5 and has an 8mm tape drive attached to
it. It also has very little useable space. Machine2 is a SUN running a
version of Solaris. I have been granted temporary access to machine2
and am loosing this access soon. I would like to backup my data on
machine2 in hopes of restoring the data to machine1 when machine1 has
enough available space.

I read the man pages for tar from SUN and these pages gave an example
of how to do what I want. Here is the procedure I used and the problem
I'm having.

Backing Up the files:
1) I telnet to machine2 and login.
2) I cd to the directory where my files are.
3) As a test, I'm backing up a single file, howard.tst. At the prompt,
   I enter: tar cvfb - 20 howard.tst | rsh machine1 -l username dd
            of=/dev/rmt0 obs=20b
   I use the -l parameter because the login ids on machine1 and
   machine2 are different.
4) The tar runs and doesn't report errors.

Checking the Restore:
1) As a test, I always like to use tar tvf to check to see where the
   restore will go (relative vs. full paths). I telnet to machine1
   and cd to my personal tmp directory.
2) At the prompt, I enter: tar tvf /dev/rmt0. I get the following
   message back:
   -rw-r--r-- 8116 108 48947 Mar 28 09:56:33 1996 howard.tst
   80 blocks on /dev/rmt0
   tar: End of tape. Mount next tape on /dev/rmt0 and type return.
3) When I press return, I get:
   proceeding to device /dev/rmt0
   tar: tape read error: Not enough space

Restoring the files to machine1:
If I login to machine1 and try to restore the files using:
tar xvf /dev/rmt0, I get:
     x howard.tst, 48947 bytes, 96 tape blocks
     80 blocks on /dev/rmt0
     tar: End of tape. Mount next tape on /dev/rmt0 and type return.
I press return and get:
     proceeding to device /dev/rmt0
     tar: tape read error: Not enough space
My file is restored, but it is missing the bottom portion of the file.
The entire file isn't restored, only a piece of it is restored.

The problem I'm having appears to have something to do w/ IBM vs. SUN
tar and dd. As a test, I ran the same procedure listed above replacing
machine1 w/ a SUN SPARC20 running Solaris v2.4. I was able to
successfully restore the files I remotely backed up.

Probably the best method for doing what I want to do would be to ftp
the files over from machine2 to machine1 and perform the tar. The
problem w/ this solution is that machine1 doesn't have the required
space for this procedure. Bob Fulwiler suggested compressing the files
on machine2. Even compressed, I would not have enough space to ftp the
files over to machine1.

If anyone can shed some more light on the problem and provide me w/ a
solution, I would appreciate the help.

Thanks to:
Mark Anderson
Alex Finkel
Bob Fulwiler
Glenn Satchell

Special thanks to both Mark Anderson and Glenn Satchell who have
helped me previously with problems I have posted to this group. I also
see their names listed frequently in the "thank you" sections of other
posts. It is people like Mark and Glenn that make this list work.
Everyone can post a problem, but it takes a special individual to take
the time to read a post and respond with a solution knowing that they
will not receive any financial returns for their effort. Thanks a
bunch guys!

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