[Fedora-livecd-list] RFC- unionfs persistence?

[Douglas McClendon]

Phillip Lougher wrote:
> Jeremy Katz wrote:
>> On Mon, 2007-09-10 at 10:15 -0500, Douglas McClendon wrote:
>>> What do people think about using unionfs for persistence (and perhaps 
>>> Copy-On-Write in general) in Fedora LiveCDs?
>>
>> The big question today is the same as the big question around using
>> unionfs for anything has been for a while now -- what's the actual
>> likelihood of an implementation ever being both upstream and stable.
> 
> In Ubuntu unionfs has been used in the liveCD for a number of releases.
> The trick is to get a Unionfs that works and stick with it, for that
> reason the Ubuntu kernel has stayed with Unionfs 1.2 and 1.4 for
> a long time.  Unfortnately we've upgraded to Unionfs 2.1.1 because
> Unionfs 1.x doesn't handle NFS filesystem branches correctly in
> recent kernels.
> 
> Having moved to 2.1.1 I expect a number of issues may arise with
> the Ubuntu liveCD, and in fact I'm currently investigating an issue that
> may be caused by the move to 2.1.1.
> 
> So the stability of Unionfs still appears to be a major issue for
> anyone using it.

Thanks for the war stories.  Bummer.  I had been hoping that the answer 
would be a little more like "yeah, with the widespread usage in ubuntu, 
and the 2.0 rewrite, and the 8 months in -mm, it's now rock solid".

But maybe it'll get there soon.  I am interested to hear what davej says 
and if it'll make it into fedora anytime soon, even given current lack 
of rock-solidness.  The more I think about it, the more I like my idea 
of having an initramfs that supports both dm and unionfs for cow...

-dmc