Second Backup Seems to Duplicate Files

Running Duplicacy from my UNRAID box, to back up my photo’s (~80 GB) directory to BackBlaze B2. My first backup seemed to go relatively smoothly, took a while, but ~80GB ended up in the bucket as expected…(although I expected some compression, I’m ok with that!).

duplicacy init documents b2://bucket-name

Had set up a scheduled script to back up once a week, and having added ~1GB of photo’s expected the Bucket size to be ~81GB on completion, checked in the next day and it looked to be >100GB. Looks like it’s backing up the entire directory again. Have I misunderstood how Duplicacy works?

duplicacy backup

I did some experiments, so set up another bucket with a new Duplicacy backup initialised in an empty directory. Then added a new doc “Doc1.txt” and backed up. Checked the bucket and 1 file present. Deleted the file, and ran backup and checked the bucket and now 3 files present. I expected 0 files?

Any help or anything obvious I’m missing greatly appreciated!

Is this the full command you used? Unless you use the -hash option or something updates the modification timestamps on all of the files since the last backup, then duplicacy has no reason to even read the files that have already been backed up.

Which directory in the bucket were the files in? There are separate folders for chunks and revisions. And there’s also the config file, of course.

Run duplicacy check -tabular. This will tell you how effective the deduplication is.

I think it may be chunk size related. Running some more tests with some larger files to test currently.