Warnings when recreating database - No block hash found for file

sylerner · August 9, 2020, 10:20pm

I had to recreate my database, and received over 400 warnings. They seem to all be of the following type:

2020-08-09 17:23:10 -04 - [Warning-Duplicati.Library.Main.Operation.RecreateDatabaseHandler-MissingBlockHash]: No block hash found for file: /home/sylerner/.config/bcompare/BCLOCK_0
2020-08-09 17:23:10 -04 - [Warning-Duplicati.Library.Main.Operation.RecreateDatabaseHandler-MissingBlockHash]: No block hash found for file: /home/sylerner/.config/filezilla/lockfile
2020-08-09 17:23:10 -04 - [Warning-Duplicati.Library.Main.Operation.RecreateDatabaseHandler-MissingBlockHash]: No block hash found for file: /home/sylerner/.config/gconf/apps/%gconf.xml
2020-08-09 17:23:11 -04 - [Warning-Duplicati.Library.Main.Operation.RecreateDatabaseHandler-MissingBlockHash]: No block hash found for file: /home/sylerner/.config/libaccounts-glib/accounts.db-wal
2020-08-09 17:23:11 -04 - [Warning-Duplicati.Library.Main.Operation.RecreateDatabaseHandler-MissingBlockHash]: No block hash found for file: /home/sylerner/.config/menus/applications-merged/xdg-desktop-menu-dummy.menu

What do these warnings mean, and is it in any way an indication that my backup files are not complete or are otherwise not intact?

Thanks.

ts678 · August 12, 2020, 8:02pm

No prior reports of that on the Internet, so interpretation will be hard. Looks kind of like a backup dlist file has some malformed contents for some small files less than blocksize. Is yours at the default of 100 KB?

Processing a small file is what the dlist file should have for a small file entry. Some of your file names look like they might possibly also give access issues (probably more likely on Windows though) due to locking.

Hard to say with small sample given, but can you see any pattern in the 400 warnings? Do any files show up multiple times (hard to spot by eye, but you could give it a try)? I think old file info generally propagates into new backup version when files don’t change, so it might be possible to propagate an internal problem.

You should also be able to see the dlist files announced as they’re read for processing, if you use verbose log, using either About → Show log → Live → Verbose or log-file=<path> with log-file-log-level=verbose.

Would you happen to have an older database around, to look into? And what prompted the Recreate run?

You could certainly try a more limited Recreate, such as the creation of the partial temporary database by Direct restore from backup files. This can be done on the same system. It will build a separate database.

What release is this, and do you know what prior releases have been running, or when last Recreate ran?

github.com

duplicati/duplicati/blob/082a14fc22efdef226c1bee956f85009f7104fb3/Duplicati/Library/Main/Operation/RecreateDatabaseHandler.cs#L259-L267


      
          if (fe.Size <= blocksize)

          {

              if (!string.IsNullOrWhiteSpace(fe.Blockhash))

                  restoredb.AddSmallBlocksetLink(fe.Hash, fe.Blockhash, fe.Blocksize, tr);

              else if (m_options.BlockHashAlgorithm == m_options.FileHashAlgorithm)

                  restoredb.AddSmallBlocksetLink(fe.Hash, fe.Hash, fe.Size, tr);

              else

                  Logging.Log.WriteWarningMessage(LOGTAG, "MissingBlockHash", null, "No block hash found for file: {0}", fe.Path);

          }

I’m not familiar with this code, but I guess I should ask if you have any custom options for hash algorithms.