RFC: Btrfs snapshots feature for F13

[Josef Bacik]

On Tue, Nov 17, 2009 at 2:48 AM, Jeff Garzik <jgarzik at pobox.com> wrote:
> On 11/17/2009 02:43 AM, nodata wrote:
>>
>> Am 2009-11-17 01:55, schrieb Chris Ball:
>>>
>>> Hi,
>>>
>>> I've written up a draft of an F13 filesystem rollback feature using
>>> Btrfs snapshots that are automatically created by yum:
>>>
>>> https://fedoraproject.org/wiki/Features/SystemRollbackWithBtrfs
>>>
>>> It'd be great to get feedback on whether this is the right idea, and
>>> how exactly the UI interaction should work, before submitting this
>>> formally.
>>>
>>> Thanks!
>>>
>>> - Chris.
>>
>> So this will confuse things a lot if the user doesn't have only rpm
>> stuff on one partition, and everything else on another. This is
>> potentially a major risk. How would that be handled?
>
> Mr. nodata,
>
> As the URL notes under "Detailed Description," that is not handled at all.
>  It wraps all file I/O, yum or not, into the snapshot.
>
> A bloody awful solution, especially when you consider that btrfs' maintainer
> Chris Mason is adding support for real userland transactions (via some
> additional ioctls).
>

Yeah but you can't roll back userland transactions.  Not to mention
you are talking about an interface that may change quite a bit over
the next year.  We have snapshotting abilities now, and yes it's a big
hammer, but just because its a bit of a blunt instrument doesn't mean
we shouldn't take advantage of it.  Thanks,

Josef