Yes. In your setup all the incremental-unfilled are deltas with respect to the last incremental-filled (see the level column). And if you delete the last incremental (which is filled, level 0), the system will fill the previous one and refer all the others to it, so you never end with a broken chain.
From the documentation (https://backuppc.github.io/backuppc/BackupPC.html#Overview): - Backups are stored as "reverse deltas" - the most recent backup is always filled and older backups are reconstituted by merging all the deltas starting with the nearest future filled backup and working backwards. - Since the most recent backup is filled, viewing/restoring that backup (which is the most common backup used) doesn't require merging any deltas from other backups. - The concepts of incr/full backups and unfilled/filled storage are decoupled. The most recent backup is always filled. By default, for the remaining backups, full backups are filled and incremental backups are unfilled, but that is configurable. - Any backup can be deleted (deltas are merged into next older backup if it is not filled). - The reverse deltas allow "infinite incrementals" - no need for a full backup if you are willing to trade speed for the risk that a file change will not be detected if the metadata (eg, mtime or size) doesn't change. Regards, Guillermo On Thu, Feb 13, 2020 at 1:14 PM Gandalf Corvotempesta <gandalf.corvotempe...@gmail.com> wrote: > > So, this is a perfectly working system: > https://postimg.cc/PCZgN634 > > with *ALL* backups available totally ? > I'll be able to restore *any* file from *any* backup , in example, > even from the #18 ? > > Il giorno gio 13 feb 2020 alle ore 16:07 Michael Huntley > <mich...@huntley.net> ha scritto: > > > > Hi Gandalf, > > > > Not with v4. V4 uses reverse deltas, so your most recent backup is a > > filled, or complete backup. > > > > V4 calculates the difference between today and yesterday, and so on > > backwards. Just think of it as incrementals going back in time and > > carrying your full with you each day. You have a full basket of goodies > > each day and leave a trail behind you. > > > > You can also have older filled backups to reduce restore time as it lessens > > the calculations BackupPC must perform. > > > > So, if you have a complete trail of incrementals going back two weeks there > > is no data loss in that time period. > > > > If I am incorrect in any way in my analogy I am sure the list will correct > > me and we will both learn. > > > > Kind regards, > > > > mph > > > > > On Feb 13, 2020, at 3:49 AM, Gandalf Corvotempesta > > > <gandalf.corvotempe...@gmail.com> wrote: > > > > > > Just a confirm: > > > > > > if I have a full backup done on 2020-01-14 (doing 1 full each month) > > > and daily incrementals, keeping up to 14 incrementals, I have data > > > loss ? > > > > > > In example, the incremental done yesterday (2020-02-12), is relative > > > to the incremental done on 2020-01-14 ? > > > > > > How does it work, exactly ? I have some "broken chain" ? > > > > > > With bacula, in example, I need at least 1 full backup and then each > > > incremental after it, to restore from yesterday. When using > > > differentials, I need 1 full, all differential, and all incrementals > > > > > > > > > _______________________________________________ > > > BackupPC-users mailing list > > > BackupPC-users@lists.sourceforge.net > > > List: https://lists.sourceforge.net/lists/listinfo/backuppc-users > > > Wiki: http://backuppc.wiki.sourceforge.net > > > Project: http://backuppc.sourceforge.net/ > > > > > > > > > > > _______________________________________________ > > BackupPC-users mailing list > > BackupPC-users@lists.sourceforge.net > > List: https://lists.sourceforge.net/lists/listinfo/backuppc-users > > Wiki: http://backuppc.wiki.sourceforge.net > > Project: http://backuppc.sourceforge.net/ > > > _______________________________________________ > BackupPC-users mailing list > BackupPC-users@lists.sourceforge.net > List: https://lists.sourceforge.net/lists/listinfo/backuppc-users > Wiki: http://backuppc.wiki.sourceforge.net > Project: http://backuppc.sourceforge.net/ _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
