Hello,
In the Bacula manual I read that :
"However, one must keep in mind that if your Volume Retention period is
too short, it may prune the last valid Full backup, and hence until the
next Full backup is done, you will not have a complete backup of your
system, and in addition, the next Incremental or Differential backup
will be promoted to a Full backup. As a consequence, the minimum Volume
Retention period should be at twice the interval of your Full backups.
This means that if you do a Full backup once a month, the minimum Volume
retention period should be two months."
I don't understand why the minimum volume retention should be at least
twice the interval of the full backups .. ?
In my configuration I do a full backup every month with a volume
retension period of 45 days, and a daily incremental backup with a
volume retension period of 35 days. I don't need archives on a long
term, 1 month is enough, but I need to be able to restore a file which
has been modified 20 days ago for example (on a daily basis, that's why
I make an incremental backup every day).
If I follow the Bacula manual, the minimum volume retension should be at
least 2 months, but I don't understand why ? In my case, an incremental
backup will never be promoted to a full, right ? For example :
1 may 0:00 am : Full backup -> volume "Full-0001"
1 may 8:00 pm : Incremental backup -> volume "Incr-0001"
2 may 8:00 pm : Incremental backup -> volume "Incr-0002"
3 may 8:00 pm : Incremental backup -> volume "Incr-0003"
...
31 may 8:00 pm : Incremental backup -> volume "Incr-0031"
1 june 0:00 am : Full backup -> volume "Full-0002"
1 june 8:00 pm : Incremental backup -> volume "Incr-0032"
2 june 8:00 pm : Incremental backup -> volume "Incr-0033"
3 june 8:00 pm : Incremental backup -> volume "Incr-0034"
...
(around 15 june Incr-0001 should be recycled)
1 july 0:00 am : Full backup -> volume "Full-0001" (recycled)
etc
So in this configuration I will always have a valid Full backup every
month and an incremental backup for every day of this month, and I don't
see any situation where an incremental backup would be promoted to a
full or that my last valid full backup would be pruned.. ?, so why
should the minimum volume retention be at least twice the interval of
the full backups (60 days in this example) ?
Thanks for your answers,
Julien
--
Julien Cigar
Belgian Biodiversity Platform
http://www.biodiversity.be
Université Libre de Bruxelles (ULB)
Campus de la Plaine CP 257
Bâtiment NO, Bureau 4 N4 115C (Niveau 4)
Boulevard du Triomphe, entrée ULB 2
B-1050 Bruxelles
Mail: jcigar AT ulb.ac DOT be
@biobel: http://biobel.biodiversity.be/person/show/471
Tel : 02 650 57 52
------------------------------------------------------------------------------
_______________________________________________
Bacula-users mailing list
Bacula-users AT lists.sourceforge DOT net
https://lists.sourceforge.net/lists/listinfo/bacula-users
|
