Aaron,
You are right some dump works on directory but amanda doesn't use the -T
parameter.
It is a dangerous option, all backup program working with a timestamps
(all dump flavour and star) have the same problem. If a directory is
moved across the directories you backup, it is not include in the dump
until the next full.
GNUTAR doesn't have this problem because it keep a complete list of
files, not just a timestamps.
A small example of the problem:
/home is the root of the partition, you have two files:
/home/foo/a/b/c
/home/bar/c/b/a
You backup the two directory separately.
You have the following backup sequence and one user operation:
/home/foo /home/bar TAPE
day 1 0 1 tape-01
day 2 1 1 tape-02
day 3 1 1 tape-03
day 4 1 1 tape-04
day 5 1 0 tape-05
a user do: mv /home/foo/a /home/bar
day 6 1 1 tape-06
day 7 1 1 tape-07
day 8 0 1 tape-08
day 9 1 1 tape-01
day 10 1 1 tape-02
day 11 1 1 tape-03
day 12 1 0 tape-04
/home/bar/a/b/c will not be in the backup of /home/bar until day 12 on
tape-04
If you restore the backup for day 6 or 7
/home/foo level 0 on tape tape-01, level 1 on tape tape-06 or tape-07
/home/bar level 0 on tape tape-05, level 1 on tape tape-06 or tape-07
then you end up with no /home/bar/a/b/c file, and no /home/foo/a/b/c
file, you can recover /home/foo/a/b/c from level 0 of /home/foo on
tape-01, but how do you know the user moved the files.
That's worse, after day 9 and overwrite of tape-01, the a/b/c file is
not on tape, there is no way to recover it
On day 12, it will be on the level 0 backup of /home/bar.
Jean-Louis
Aaron J. Grier wrote:
On Thu, Oct 02, 2008 at 10:15:52AM -0400, Jean-Louis Martineau wrote:
sendbackup: info end
| DUMP: You can't update the dumpdates file when dumping a subdirectory
| DUMP: The ENTIRE dump is aborted.
sendbackup: error [dump (20830) /sbin/dump returned 1]
Like the message says: You can't use DUMP to backup a subdirectory, DUMP
work only on partition.
You must use GNUTAR to backup a directory.
I beg your pardon, but /sbin/dump is perfectly capable of dumping
subdirectories on most unixes. it just won't record (or read) the date
of the dump in /etc/dumpdates.
a lot of /sbin/dump will accept a -T parameter to specify a date for
incrementals. I assume tar requires a similar parameter, perhaps it
could be used with /sbin/dump as well?
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