Status to make btsfs to the standard filesystem of Fedora

[Adam Williamson]

On Thu, 2013-01-24 at 19:56 -0700, Chris Murphy wrote:
> On Jan 24, 2013, at 5:44 PM, Adam Williamson <awilliam at redhat.com>
> wrote:
> > 
> > Just about everything in btrfs is really different :) I'm still
> wrapping
> > my head around it too. But as far as possible, the 'legacy' tools
> should
> > show something as accurate and useful as they can, I believe.
> 
> For mount, the only issue I know of is that it doesn't show subvolume
> mounted. Ubuntu reportedly does (I don't use it so I can't
> confirm/deny), even though it's using older btrfs-progs, and older
> linux-utils. So I'm not sure why Fedora doesn't show subvolumes in
> mount. I have to do cat /proc/self/mountinfo to get this information
> on Fedora.
> 
> For df, it's maybe more challenging. The use cases where it's a
> problem: small devices, e.g. less than 100GB and also not formatted
> with the mixed data/metadata option; and pushing the usage of a device
> of any size to nearly it's full capacity (beyond 90%). But even a
> scale algorithm that changes the Capacity % bias from predominantly
> data, to predominantly metadata doesn't fix the problem. 
> 
> e.g. 95% Capacity per df, with a heavy metadata usage of the file
> system. Further metadata heavy writes might mean you're actually at
> 99% Capacity, whereas with minimal metadata writes might mean you're
> at 92% capacity. So which is correct to report? It depends on future
> usage, which is unknown. Small problem.

Well that's not the one I was thinking of, actually - I believe I was
hit by cases where some subvols use redundancy, in which case df goes
completely wrong. I'd have to re-install and re-check to be sure of
exactly what I saw go wrong, though.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
http://www.happyassassin.net