33.6. Making backups with dump

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:

[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
  

[root@deep] /# dump -3u -f  /dev/st0 /home

[root@deep] /# dump -2u -f  /dev/st0 /home

[root@deep] /# dump -5u -f  /dev/st0 /home

[root@deep] /# dump -4u -f  /dev/st0 /home

[root@deep] /# dump -7u -f  /dev/st0 /home

[root@deep] /# dump -3u -f  /dev/st0 /home

[root@deep] /# dump -2u -f  /dev/st0 /home

[root@deep] /# dump -5u -f  /dev/st0 /home

[root@deep] /# dump -4u -f  /dev/st0 /home

[root@deep] /# dump -6u -f  /dev/st0 /home

[root@deep] /# dump -3u -f  /dev/st0 /home

[root@deep] /# dump -2u -f  /dev/st0 /home

[root@deep] /# dump -5u -f  /dev/st0 /home

[root@deep] /# dump -4u -f  /dev/st0 /home

[root@deep] /# dump -9u -f  /dev/st0 /home

[root@deep] /# dump -3u -f  /dev/st0 /home

[root@deep] /# dump -2u -f  /dev/st0 /home

[root@deep] /# dump -5u -f  /dev/st0 /home

[root@deep] /# dump -4u -f  /dev/st0 /home

[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

1. special device file like /dev/st0, a tape drive,

2. /dev/rsd1c, a disk drive,

3. An ordinary file

4. the standard output.

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.