Sorry to insist .. but no one on this ? is it an error in the Bacula manual ?
thanks On Thu, 2009-04-02 at 12:40 +0200, Julien Cigar wrote: > 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: jci...@ulb.ac.be @biobel: http://biobel.biodiversity.be/person/show/471 Tel : 02 650 57 52 ------------------------------------------------------------------------------ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
