backintime and disk space

[pramathesh ambasta]

I am not sure whether this bug relates to backintime or to nautilus or both. I am filing it under backintime because using it exposed me to this issue.

I was using backintime to backup my documents and thunderbird mail folder (two folders, total size ~17 GB) on a separate partition on my notebook drive. The size of the partition is 25 GB. Gparted reports a usable space of around 23.28 GB.

Since backintime creates snapshots and as per their website, they only save differences to files/folders (the rest are hard links), disk usage should be incremental. However, after a couple of snapshots, the partition filled up and backintime reported an error about not completing the backup because of low disk space. Disk Usage Analyzer also warned me about the partition filling up to 100%

I checked with du/df and found that disk usage was around 19GB (or 4 GB free). When I checked the partition's properties in nautilus, it showed the snapshot folders each as occupying arond 3.9GB and the parent folder too occupying 3.9 GB.

But since backintime was complaining, I had to configure it to stop taking snapshots of the mail folder. It is now backing up only my Documents folder and has stopped complaining.

However, this can only be treated as a work around. Since backintime uses hard links, disk space should not fill up. This is what I have understood from their website (for example, https://answers.launchpad.net/backintime/+question/146072).

So is the file system or nautilus mis-reporting disk space?

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: backintime-gnome 1.0.6-1
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Architecture: i386
Date: Wed Jul 6 13:43:04 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: backintime
UpgradeStatus: No upgrade log present (probably fresh install)

[Tom (tom-reportbug)]

backintime also archives data about file attributes during each snapshot in a way that is not incremental. On my system, these ancillary non-hard-linked files take about a half gigabyte per backup.

[Germar (germar)]

This could have been a filesystem which doesn't support hard-links. Take a look at the FAQ below on how to check if snapshots are incremental
https://answers.launchpad.net/backintime/+faq/2403

I'll close this bug as it is probably solved by now.