Another way to look at this issue would be that backup frequency and retention should be orthogonal. When and how you run a backup shouldn't change the fact that the existing data should be retained for however long the original policy stated.
Skylar On Wed, Sep 9, 2015 at 7:21 AM, John Stoffel <j...@stoffel.org> wrote: > >>>>> "Edward" == Edward Ned Harvey (lopser) <lop...@nedharvey.com> > writes: > > >> From: tech-boun...@lists.lopsa.org [mailto:tech-boun...@lists.lopsa.org > ] > >> On Behalf Of Edward Ned Harvey (lopser) > >> > >> Just before midnight, I destroyed the machine. And then I started doing > the > >> restore. Guess what time the backup script runs? Midnight. Guess what > its > >> behavior is? It notices the filesystem is completely different, so it > sends a > >> new "Full" and clobbers the backup destination. Hooray! :-) > > Edward> BTW, every mode of backup is prone to failure, so I generally > Edward> like to use more than one type of backup. In this case, I had > Edward> the machine snapshots, and I also periodically export the > Edward> config (it's a firewall VM). So I was able to rebuild the > Edward> machine from scratch and then restore the config. > > I think the root cause of your failure here is that you assume ONE > full backup is all you need. Instead you should be keeping multiple > full backups instead. > > > Edward> So what kind of backup script clobbers the backup destination? > Edward> It's my own script, and here's the algorithm: > > Edward> foreach filesystem as "fs" on source: > Edward> if fs exists on dest: > Edward> if source fs and dest fs have a snapshot in common: > Edward> send incremental source fs to dest fs > Edward> else: > Edward> rename dest "fs" to "fs_to_destroy" > Edward> send full source fs to dest fs > Edward> if send completed successfully: > Edward> destroy fs_to_destroy from dest > Edward> else: > Edward> // put it back the way it was > Edward> rename dest "fs_to_destroy" to "fs" > Edward> else: > Edward> send full source fs to dest fs > > Here is should be: send a NEW full source FS to dest FS, leaving > other Full(s) alone. > > _______________________________________________ > Tech mailing list > Tech@lists.lopsa.org > https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech > This list provided by the League of Professional System Administrators > http://lopsa.org/ >
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