Call for agenda for Workstation WG meeting 2014-Dec-17

[Chris Murphy]

On Wed, Dec 17, 2014 at 3:56 PM, Josh Boyer <jwboyer at fedoraproject.org> wrote:
> On Wed, Dec 17, 2014 at 5:45 PM, Chris Murphy <lists at colorremedies.com> wrote:
>> On Tue, Dec 16, 2014 at 12:21 PM, Josh Boyer <jwboyer at fedoraproject.org> wrote:
>>> Your requests aren't bad at all, but they aren't new.  Everyone wants
>>> btrfs because it was hyped as the filesystem of the future.
>>
>> tl;dr Those who want it, want it for the features, and much simpler
>> access to those features. Not because of hype.
>
> tl;dr I know all of that.  It still doesn't change the fact that the
> features are tied to a filesystem that isn't actually read yet.  It
> doesn't matter how simple it is to use if it doesn't actually keep
> your data safe.

I was responding to the hype assertion. OK so now about the suggestion
it doesn't keep data safe...

What's this based on? It connotes data on Btrfs commonly isn't safe on
stable hardware.

How about, "you can yank the power cable 1000 times and the filesystem
survives with no abnormalities, and does not require an fsck" in which
case it's safer than ext4 or XFS based on [1] and [2]. That is just
one test, and it's probably on well behaved hardware. But I don't know
of any other side by side comparison like this, in particular one
suggesting Btrfs isn't keeping user data safe.

Ok so what's Fedora's "Btrfs is ready" metric? It used to be that an
fsck needs to ship. Ok, there's been one for a while. Is the real
metric that the fsck needs to fix use cases x, y, and z even though
those aren't listed anywhere? OK fine, it just needs to work better
and the various repair methods need consolidation, all reasonable but
not stated as the thing that makes it ready.

What if it turns out Btrfs needs fsck less often in the first place,
and what remains to be fixed by an offline fsck is just really hard to
fix, hence a higher fsck fail rate?

Opensuse 13.2 by default puts /home on XFS, and everything else on
Btrfs. Did Fedora consider this? Should it be considered? It gets
around having to answer the question whether it's ready for user data,
by using it for more easily replaceable system data should it go belly
up. And in the meantime provides a means for online atomic updates and
dropping the immediate reboot requirement; and rollbacks; and dropping
the complexities (to users and admins alike) of LVM.

Also, opensuse 13.2 doesn't appear to limit Btrfs by default on
command line as far as I can tell. I can create and use multiple
device Btrfs volumes, including raid56, autodefrag, compression, and
send/receive all work.


[1] http://events.linuxfoundation.jp/sites/events/files/slides/linux_file_system_analysis_for_IVI_systems.pdf
    slide 21
[2] https://events.linuxfoundation.org/sites/events/files/slides/Btrfs_Current%20status_and_future_prospects_0.pdf
    slide 8



-- 
Chris Murphy