I know Matt corrected this post, but I wanted to address this: --- If you do a --verify-at-time xyz where xyz is your oldest backup, it should verify all files in that backup - so every delta should be applied. This should verify that all delta's (backups) are good and functioning.
[In short, it "verifies" that for each file for which a successful verify is returned, that the most current file, all applicable delta's and meta-data are good and functioning properly.] --- However, if files were added after the initial backup, I'd guess that a verify won't check the delta's for those files - since they don't exist in the set at time xyz So, while a verify to your oldest backup is good, it's not comprehensive for all files that have deltas+meta-data. --- I'm not aware, so if I'm wrong perhaps someone could correct me, but I'd like a command to, in essence, do a comprehensive --verify-all-files-in-the-archive. [I'm pretty sure such a thing doesn't exist, at least I never saw it in the docs.] This would apply all deltas to *all* files (back to the oldest copy) and compare the stored hashes at the time of backup to the rebuilt file. [Note all the files, not just those in a particular target date/delta.] This wouldn't verify that every file would be correct in every delta version, but it would, I think, get as close as one might come to that. Then again, doing an intermediate check of the hash and file at each delta point wouldn't take too much longer [or so I think without a lot of time invested in pondering it] - so if this option/feature doesn't exist and one were to code it, it might not be much more code or difficulty... Thoughts? -Greg > Daniel Miller wrote: >>> I think you are misunderstanding how --verify works. If you say: >>> >>> rdiff-backup --verify-at-time 1Y >>> >>> it does not verify the last 1 years worth of backups. It verifies a >>> single backup a year ago (I believe the closest backup before that exact >>> time); hence the name "verify-at-time". >> >> Yes, I do understand that. But to verify a one-year-old backup it must >> apply each set of differential data over that entire year to reconstruct >> the files as they existed one year ago. > That is incorrect. "Every 10 incremental diffs, rdiff-backup stores > another snapshot of the file. [...] During the restore, rdiff-backup > finds the oldest snapshot at least as recent as the desired backup time > (it could be the current mirror, or one of these snapshots)." > (http://www.mail-archive.com/rdiff-backup-users@nongnu.org/msg03884.html). >> I'll address your second assertion first: I'm getting less verification >> than I thought. I maintain that it is effectively verifying the >> integrity of every backup increment between now and the point in time >> that I verify since it uses each of those increments to construct the >> point in time that I'm verifying. Please explain how my understanding is >> wrong. > This follows from what I noted above. To do a verify at 1Y ago, it will > (on average) only process 5 rdiffs. It may process 10 or 0, but that's > the average. You are only verifying the backups immediately after the > 1Y ago mark. > Matthew Flaschen _______________________________________________ rdiff-backup-users mailing list at rdiff-backup-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/rdiff-backup-users Wiki URL: http://rdiff-backup.solutionsfirst.com.au/index.php/RdiffBackupWiki
