Re: Tape Question..

[Craig Sanders <cas@taz.net.au>]

On Wed, Aug 21, 2002 at 12:14:06PM +0800, axacheng wrote:
> I have a big size file about 33G in /home directory !!! and i wanna
> backup this file into tape device....
> 
> Unfortunately, My tape just 24G(compressd).....so that i must be
> change tape when data write into tape device...
> 
> How should i do???  
> 
> shell > tar cjvf /dev/st0 /home       (IT IS NOT WORKING! Because, my
> tape maxima size only 24G )

there are numerous options available to you.

the most obvious is the -M (--multi-volume) option of tar, possibly
combined with the -L (--tape-length) option if tar can't properly detect
the end of a tape on your system.  see the info docs for tar, search for
"Using Multiple Tapes".

or see the man page for the split(1) command.

another option is to manually divide the backup into multiple smaller
pieces.  e.g. backup /home/[a-k]* on one tape, and /home/[l-z]* on a
second tape, or whatever division actually fits on the tapes.

yet another option is to use a backup system such as afbackup, amanda,
taper, etc to do your backups.  some of these know how to deal with
multi-volume backups and automatically ask you to change tapes when
required.  they will also allow more sophisticated backup strategies
such as a weekly full backup plus daily incremental backups.

IMO, the last option is the best.  your backup needs have grown beyond
the ability of a simple tar command.

i highly recommend the book _Unix Backup & Recovery_ by W. Curtis
Preston (published by O'Reilly & Associates).  it is an excellent
introduction to unix backup tools & strategies.  implement a quick &
dirty fix with something like "tar cMf /dev/st0 /home" for now and then
read this book to help you figure out a better long-term solution.


craig

-- 
craig sanders <cas@taz.net.au>

Fabricati Diem, PVNC.
 -- motto of the Ankh-Morpork City Watch