LiveCDUnion
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⇤ ← Revision 1 as of 2009-06-09 16:57:37
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← Revision 2 as of 2009-06-10 07:37:02 ⇥
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| * '''Launchpad Entry''': UbuntuSpec:foo | ## * '''Launchpad Entry''': UbuntuSpec:foo |
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| == Design == The Karmic kernel already has dropped AUFS as it did not port forward without work. |
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| This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like: | The Karmic kernel already has dropped AUFS as it did not port forward without work. This leaves us with no liveCD. |
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| === Code Changes === | Evaluate the alternative options: |
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| Code changes should include an overview of what needs to change, and in some cases even the specific details. | 1. DM COW snapshots 1. fuse union mount 1. VFS union mount 1. AUFS 1. UnionFS |
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| === Migration === | Retool to use the selected solution. |
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| Include: * data migration, if any * redirects from old URLs to new ones, if any * how users will be pointed to the new way of doing things, if necessary. |
=== DM COW snapshots === These work but the filesystems the create are not rsync friendly. This limitation is very problematic for QA who use this feature to make ISO testing cheaper. === FUSE Union Mount === This was tested and does seem to work, but performance is poor. This work will be retained for the === VFS Union-Mount === This seems to be the communities preferred platform. http://lkml.org/lkml/2009/5/18/289 http://people.ubuntu.com/~scott/vfs-union/ http://valerieaurora.org/union/ === AUFS === === UnionFS === |
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| It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during testing, and to show off after release. Please add an entry to http://testcases.qa.ubuntu.com/Coverage/NewFeatures for tracking test coverage. This need not be added or completed until the specification is nearing beta. |
TBD |
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| This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved. == BoF agenda and discussion == Use this section to take notes during the BoF; if you keep it in the approved spec, use it for summarising what was discussed and note any options that were rejected. |
It is unclear the VFS union-mount will be merged in time for 2.6.31 which would mean carrying it as a patch set much as we carry AUFS now. |
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Contributors:
Packages affected:
Summary
We use union filesystems to implement the live cd experience. In Jaunty this was implemented using AUFS. However this is not expected to ever make it upstream. The currently favourite implementation of this style of functionality is VFS union-mount. The purpose of this spec is to track both the progress upstream of the required functionality as well as enumerating the other options.
Release Note
None required as there should be no user visible change.
Rationale
The current AUFS support is buggy and not likely to make it upstream. We should be trying to move to the upstream solution as it becomes available. Any help and testing we can provide them can only help its integration.
Assumptions
VFS union-mount will be sufficiently stable, performant, and feature complete to allow it to replace the current AUFS implementation.
Implementation
The Karmic kernel already has dropped AUFS as it did not port forward without work. This leaves us with no liveCD.
Evaluate the alternative options:
- DM COW snapshots
- fuse union mount
- VFS union mount
- AUFS
- UnionFS
Retool to use the selected solution.
DM COW snapshots
These work but the filesystems the create are not rsync friendly. This limitation is very problematic for QA who use this feature to make ISO testing cheaper.
FUSE Union Mount
This was tested and does seem to work, but performance is poor. This work will be retained for the
VFS Union-Mount
This seems to be the communities preferred platform.
http://lkml.org/lkml/2009/5/18/289 http://people.ubuntu.com/~scott/vfs-union/ http://valerieaurora.org/union/
AUFS
UnionFS
Test/Demo Plan
TBD
Unresolved issues
It is unclear the VFS union-mount will be merged in time for 2.6.31 which would mean carrying it as a patch set much as we carry AUFS now.
KernelTeam/LiveCDUnion (last edited 2009-06-10 07:37:02 by 41)