Union mounts are an alternative to unionfs and aufs. There has been more work on them upstream since last cycle evaluate whether they are ready to replace aufs.

Release Note

We primarily use the Union Filesystem solution to provide the live CD environment, therefore if union-mounts is feature complete enough to provide the live cd environment it would be possible to switch to it for the distributions use case. However we would be deprecating aufs in the process as the patch sets collide.

  • The AUFS filesystem has been deprecated in favour of the upstream favoured union-mounts patch set. Users of AUFS specific functionality should remain on Lucid


Union-mounts is seen as the upstream approved way to get union filesystem style support. We wish to minimise our delta from upstream using upstream features wherever possible.

User stories


union-mounts patches are feature complete and stable in time for Maverick, and review is showing they are very likely to merge to mainline.


We will pull back the union-mounts patch kit to the Maverick kernel and offer it for testing.

Test/Demo Plan


Discussion Notes

Discussion was short, there are now patches which claim to be feature complete. These need review, evaluation and testing. To this end we propose to make a PPA with a patched kernel and tools for testing. Once this testing is done we will evaluate whether they are feature rich enough to allow use for the LiveCD, and based on that consider them for Maverick. Updates for AUFS will be held off until this is determined.


KernelTeam/Specs/KernelMaverickUnionMounts (last edited 2010-05-17 14:00:15 by apw)