[Yum-devel] [PATCH 0/3] yum-utils: fs-snapshot support for LVM snapshots

[Mike Snitzer]

On Wed, Feb 03 2010 at 10:07am -0500,
Seth Vidal <skvidal at fedoraproject.org> wrote:

> 
> 
> On Wed, 3 Feb 2010, Mike Snitzer wrote:
> 
> >This patch series adds LVM snapshot support to yum-utils' fs-snapshot
> >plugin.  LVM and DM now support "snapshot-merge" to allow changes stored
> >in a snapshot LV to be merged back into the snapshot's origin LV.
> >
> >This LVM/DM support allows for "system rollback" of any filesystem that
> >is built on LVM logical voluems that can be snapshotted.  Adding LVM
> >snapshot support to the yum-utils fs-snapshot plugin extends the utility
> >of this plugin beyond btrfs filesystems.  The fs-snapshot's support for
> >LVM snapshots is disabled by default.
> >
> >I would like to get this support committed upstream at your earliest
> >convenience.  As such I welcome any review/feedback on these changes.
> >
> >It is my hope that these changes can still make F13 as part of the
> >"System Rollback" feature.  The existing project Feature page could be
> >extended to include LVM snapshot information:
> >http://fedoraproject.org/wiki/Features/SystemRollbackWithBtrfs
> >
> >[please cc me when replying as I'm not subscribed to yum-devel]
> 
> 
> 
> My only question about your changes is:  how well has this been tested?

I have tested this LVM snapshot support extensively using Linux
2.6.33-rc5 and LVM 2.02.60 (plus the %ORIGIN patch I just committed to
upstream LVM2; we should be making a 2.02.61 release very soon and then
rawhide will be updated accordingly).

Josef, could you test my patches against btrfs to make sure I didn't
cause the btrfs support to regress?  I'm pretty confident it should
"just work" but if you could confirm that I'd really appreciate it.

> Some feature considerations:
>  1. timing out if a backup is taking too long

I think it all current cases (btrfs and LVM snapshot) the snapshot
creation is instantaneous.  The actual "system rollback" is performed by
the user at a time of their choosing.

>  2. perhaps extending/improving the information in yum-history to
> include which snapshot most immediately preceeded a yum transaction.

Hmm, OK.. sounds like a good idea; but I'm basically a yum newbie.  Any
additional pointers would be appreciated (do I need to call a certain
method that conduit provides?).

Can this be layered ontop of my current patches?  So I don't need to
repost v2 of this patch series..

Thanks,
Mike