It's interesting to use the dump backup program if you want to take advantage of its several levels of backup procedures. Given below is a procedure to have a longer backup history and to keep both the backup and restore times to a
minimum. In the following example, we assume that the backup is written to a tape drive named /dev/st0 and we backup the home directory /home of our system.
It is important to always start with a level 0 backup, for example:
Friday 1. use tape 1 for the first full backup.
[root@deep] /# dump -0u -f /dev/st0 /home
DUMP: Date of this level 0 dump: Fri Jan 28 21:25:12 2000
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping /dev/sda6 (/home) to /dev/st0
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 18582 tape blocks on 0.48 tape(s).
DUMP: Volume 1 started at: Fri Jan 28 21:25:14 2000
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: DUMP: 18580 tape blocks on 1 volumes(s)
DUMP: finished in 4 seconds, throughput 4645 KBytes/sec
DUMP: Volume 1 completed at: Fri Jan 28 21:25:18 2000
DUMP: Volume 1 took 0:00:04
DUMP: Volume 1 transfer rate: 4645 KB/s
DUMP: level 0 dump on Fri Jan 28 21:25:12 2000
DUMP: DUMP: Date of this level 0 dump: Fri Jan 28 21:25:12 2000
DUMP: DUMP: Date this dump completed: Fri Jan 28 21:25:18 2000
DUMP: DUMP: Average transfer rate: 4645 KB/s
DUMP: Closing /dev/st0
DUMP: DUMP IS DONE
Monday. use tape 2 for the incremental backups.
[root@deep] /# dump -3u -f /dev/st0 /home
Tuesday. use tape 3 for the incremental backups.
[root@deep] /# dump -2u -f /dev/st0 /home
Wednesday. use tape 4 for the incremental backups.
[root@deep] /# dump -5u -f /dev/st0 /home
Thursday. use tape 5 for the incremental backups.
[root@deep] /# dump -4u -f /dev/st0 /home
Friday 2. use tape 6 for the incremental backups.
[root@deep] /# dump -7u -f /dev/st0 /home
Monday. use tape 2 for the incremental backups.
[root@deep] /# dump -3u -f /dev/st0 /home
Tuesday. use tape 3 for the incremental backups.
[root@deep] /# dump -2u -f /dev/st0 /home
Wednesday. use tape 4 for the incremental backups.
[root@deep] /# dump -5u -f /dev/st0 /home
Thursday. use tape 5 for the incremental backups.
[root@deep] /# dump -4u -f /dev/st0 /home
Friday 3. use tape 7 for the incremental backups.
[root@deep] /# dump -6u -f /dev/st0 /home
Monday. use tape 2 for the incremental backups.
[root@deep] /# dump -3u -f /dev/st0 /home
Tuesday. use tape 3 for the incremental backups.
[root@deep] /# dump -2u -f /dev/st0 /home
Wednesday. use tape 4 for the incremental backups.
[root@deep] /# dump -5u -f /dev/st0 /home
Thursday. use tape 5 for the incremental backups.
[root@deep] /# dump -4u -f /dev/st0 /home
Friday 4. use tape 8 for the incremental backups only if there have five Fridays in one month.
[root@deep] /# dump -9u -f /dev/st0 /home
Monday. use tape 2 for the incremental backups only if there have five Fridays in one month.
[root@deep] /# dump -3u -f /dev/st0 /home
Tuesday. use tape 3 for the incremental backups only if there have five Fridays in one month.
[root@deep] /# dump -2u -f /dev/st0 /home
Wednesday. use tape 4 for the incremental backups only if there have five Fridays in one month.
[root@deep] /# dump -5u -f /dev/st0 /home
Thursday. use tape 5 for the incremental backups only if there have five Fridays in one month.
[root@deep] /# dump -4u -f /dev/st0 /home
Month. use another tape for a new full backup when the month change.
[root@deep] /# dump -0u -f /dev/st0 /home
Where
-0 to -9 is the backup level option you want to use,
the u option means to update the file /etc/dumpdates after a successful dump,
The -f option to write the backup to file
The file may be a
special device file like /dev/st0, a tape drive,
/dev/rsd1c, a disk drive,
An ordinary file
the standard output.
Finally, you must specify what you want to backup. In our example, it is the /home directory /home.
You can see that we use the same tapes 2 to 5 for daily backups -Monday to Thursday = 4 tapes, tapes 6, 7, and 8 for weekly backups -other Fridays, 6 + 7 + 8 = 3 tapes. note that there
can be five Fridays in one month and tapes 1 and any subsequent new one for monthly backups -first Friday each month, 1 + any subsequent 11 months = 12 tapes. In
conclusion, if we use 8 tapes 4 + 3 + 1 = 8, we can have a full backup for one month and repeat the procedure with the 8 tapes to get our subsequent 11 months to come for a total of 1-year individual full backups.
The full backup should be done at set intervals, say once a month, and on a set of fresh tapes that are saved forever. With this kind of procedure, you will have 12 tapes for 12 months that handle histories and changes of your system for one year. Later, you can copy the 12 tape backups onto a different computer designated to keep all yearly backups for a long time and be able to reuse them, 12 tapes, to repeat the procedure for a new year.