Making backups with dump

Securing and Optimizing Linux: RedHat Edition -A Hands on Guide
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# 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:

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

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

2. `/dev/rsd1c`, a disk drive,

3. An ordinary file

4. 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.

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