Backblaze B2 Cloud Sync is duplicating files


Jan 20, 2018
Hi all! I'm hoping someone has encountered this before or can give me suggestions on where to start troubleshooting this, because I'm stumped.

A few months ago I set up the B2 cloud sync option on FreeNAS (direction is "push", mode is "sync") to run every hour and keep things backed up to the cloud. There was about 4TB of initial data to back up, and over a few weeks it completed the first sync successfully. I've had no problems since then, everything I added to the NAS was faithfully backed up the same day.

Today I got a notification from my ISP that I was about to hit my data usage cap, so I started investigating and found that FreeNAS has inexplicably been re-uploading all my files, the vast majority of which haven't been touched or modified in any way since the initial backup.

In addition to blowing up my data usage with my ISP, B2 keeps multiple versions of each file by default, so I'm now being charged for 2x the space it takes to actually back up my NAS. I can update their lifecycle rules to prevent multiple versions from being stored, but it still means I'm left paying for multiple terabytes of data usage, so right now I'm considering this a pretty serious bug.

I'm on FreeNAS-11.1-U4. Happy to provide any other info or troubleshooting that may be useful. Should I just submit this as a bug directly to ixsystems?
Feb 8, 2015
Did you ever solve this?
I am facing the same issue

Feb 8, 2015
The strange thin is, that the backup job is set to run daily at 01:00.
So every 2nd day it gets deleted - but not at 01:00...


Dec 19, 2012

I am having the same sort of issue. I had rclone running in a jail previously, and have switched to the cloud sync functionality in the UI. None of the files changed, but B2 is storing multiple versions.

Straight after posting I saw what it might be. I had selected Transfer Mode as Sync rather than Copy.

Docs say,
Sync makes files on the destination system identical to those on the source. Files that are removed from the source are also removed from the destination, similar to rsync --delete.

Copy copies files from the source to the destination, skipping files that are identical, similar to rsync.

So that means that Sync doesn't skip the files that are identical?