Backing up - Segment ( More Than One Archives )

[DK Raviraja]

Hi

I would like to have more than one archive in single DAT. What is the archive syntax using TAR. Similarly how to extract the same.

Hint : mt fsf,eof ...?

DKR

[Carlos Fernandez Riera]

Yous must use /dev/rmt/0mn special file instead of /dev/rmt/0m.

0mn does not rewind tape , so you can do more that one backup on a sigle tape.

try:

tar cvf /dev/rmt/0mn /tmp/1
tar cvf /dev/rmt/0mn /tmp/2
tar cvf /dev/rmt/0mn /tmp/3
mt -t /dev/rmt/0m rew
tar tvf /dev/rmt/0mn
tar tvf /dev/rmt/0mn
tar tvf /dev/rmt/0mn

[Rainer_1]

use the no rewind device for backups.

tar cvf /dev/rmt/0mn ....

this writes multiple tar backups to one tape.
After rewind (mt rew) you can go to the end of tape with

mt -t /dev/rmt/0mn eod
mt -t /dev/rmt/0mn bsf 1

to add more tar backups.

To get the first backup use

mt rew
tar xvf /dev/rmt/0mn ....

to go to the second backup use

mt rew
mt -t /dev/rmt/0mn fsf 1
tar xvf /dev/rmt/0mn ....

to go to the third backup use

mt rew
mt -t /dev/rmt/0mn fsf 2
tar xvf /dev/rmt/0mn ....

an so on.

[DK Raviraja]

Hi guys,

Can you give me two typical examples. I tried your solutions, but it is not working. I don't know where I committ mistake.

So please give example with proper command set

Thanks

[Rainer_1]

to make it simpler you could add more archives to an existing tar archive.

Make first tar archive with (using default tape device /dev/rmt/0m)

tar cv

Then add next archives with

tar rv

What you get is a single tar archive that has all archives on it.
To restore a file do

tar xv

The disadvantage of this procedure is that tar rv ... must read all the previous data written to tape before adding new data.

[Carlos Fernandez Riera]

There is no secret. Just use no rewind device

Begin rewinding tape:

mt -t /dev/rmt/xmn rew

write some tar session to tape ( always using no rewind device)

tar cvf /dev/xmn /tmp
tar cvf /var/adm/syslog
.....


then rewind tape

mt -t /dev/rmt/xmn rew

and verify

tar tvf /dev/rmt/xmn
rwx------ .................... /tmp/....
rwx------ .................... /tmp/....
...
tar tvf /dev/rmt/xmn
rwx------ .................... /var/adm/syslog
....


Read this thread too:

http://my1.itrc.hp.com/cm/QuestionAnswer/1,1150,0xb00a6d96588ad4118fef0090279cd0f9,00.html