Incremental Backup using one DLT tape.

Posted on 2005-04-16
Medium Priority
Last Modified: 2013-12-27
Hi All,

I recently posted a question on how to perform incremental backups and restores at:

I tried it with multiple tapes and everything worked fine. The question is: can I do it with one tape? Just make backups and not rewind?

Here are the partitions I have:

ufsdump 0ucf /dev/rmt/0n /
ufsdump 0ucf /dev/rmt/0n /var
ufsdump 0ucf /dev/rmt/0n /mnt1
ufsdump 0ucf /dev/rmt/0n /mnt2
ufsdump 0ucf /dev/rmt/0n /mnt3

Assuming I want to make a level 0-7 backup and I want to restore something from level 4, can it be done on the same tape?
Question by:kalmen
LVL 10

Accepted Solution

neteducation earned 2000 total points
ID: 13797040
basically yes.

However you should not keep the tape in a non-rewinded state for a long time. What you can do is the following:

You start with:

ufsdump 0ucf /dev/rmt/0n /
ufsdump 0ucf /dev/rmt/0n /var
ufsdump 0ucf /dev/rmt/0n /mnt1
ufsdump 0ucf /dev/rmt/0n /mnt2
ufsdump 0ucf /dev/rmt/0 /mnt3

then when you want to add the incrementals

mt -f /dev/rmt/0n fsf  5
ufsdump 1ucf /dev/rmt/0n /
ufsdump 1ucf /dev/rmt/0n /var
ufsdump 1ucf /dev/rmt/0n /mnt1
ufsdump 1ucf /dev/rmt/0n /mnt2
ufsdump 1ucf /dev/rmt/0 /mnt3

the mt-command is used to control the tape  fsf 5 means fordward 5 sessions (getting you to the end of the full backup.

if you want to do an increment of the increment (or in other words everything that changed since the last incremental) you'd do

mt -f /dev/rmt/0n fsf  10
ufsdump 2ucf /dev/rmt/0n /
ufsdump 2ucf /dev/rmt/0n /var
ufsdump 2ucf /dev/rmt/0n /mnt1
ufsdump 2ucf /dev/rmt/0n /mnt2
ufsdump 2ucf /dev/rmt/0 /mnt3

Even though this is technically possible I would not recommend it to much, because restoreing such a thing might get quite complicate.


Author Comment

ID: 13797107
Pefect. Thanks.

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