* Re: some feedbacks seen on btrfs
2013-06-26 21:04 some feedbacks seen on btrfs Roger Pack
@ 2013-06-27 13:50 ` Duncan
0 siblings, 0 replies; 2+ messages in thread
From: Duncan @ 2013-06-27 13:50 UTC (permalink / raw)
To: linux-btrfs
Roger Pack posted on Wed, 26 Jun 2013 15:04:56 -0600 as excerpted:
> First off, thanks for an awesome file system, it is working well for my
> purposes of compressing a filesystem on a small VPS. Woot!
>
> I thought I'd call out a few things (in the hopes of spurring
> improvements) I'd seen about btrfs (in case they weren't common
> knowledge...):
These are common knowledge... for the folks on this list, anyway. The
problem tends to be distros that make the still experimental and getting
new features btrfs an easily used option (or even default?), for people
to use, without making the caveat about btrfs still being under heavy
development and needing good backups equally obvious if not more so than
the option to use btrfs in the first place.
FWIW, I tried btrfs about a year ago and it simply wasn't ready for me.
I tried it again this year (from about a month ago on), however, and thru
a combination of my needs changing somewhat and btrfs maturing
dramatically in the intervening year, I've been far happier with how it's
going now.
Generally speaking, used as a traditional-use single-device filesystem,
btrfs is /reasonably/ stable and mature now, altho because it's still
actively getting new features and likely will be for several more kernel
cycles yet, it's not yet ready for the full production-ready stability
seal and delivery just yet.
The multi-device raid1 mode (well, two-way-mirroring, it's not full N-way
mirroring raid1, despite the name) as well as raid0 striping and raid10
both, is in the middle, the features are there and complete, and some
stabilizing has been done, but it's not as stable as the traditional-use
single-device code is yet. Still, this being my area of interest and
usage, it's in this area that I saw the biggest changes in the last year,
such that it's now usable for my use case, dual-device SSD in raid1 mode
for both data and metadata -- with good backups around just in case!
Subvolumes and snapshots aren't my primary use case or focus, but I'd put
them in the same category as raid0/1/10, middle level toward stability,
code implemented for awhile and generally working, but not as mature or
stable as the traditional filesystem use-case.
The brand new raid5/6 mode code was new to kernel 3.9 and isn't yet
complete. Certainly with 3.9, and to a lessor extent with 3.10, it's
EXPECTED to have problems in power-drop situations, etc, as that's the
part of the code that isn't finished yet. (AFAIK it's basically complete
with 3.10, but is still first-implementation code without anything beyond
first-implementation bug testing, so don't trust 3.10 for raid5/6 mode
either.) By 3.12 or so, it should be starting to get there, and by
spring of next year, I'd guess the code should be about where raid0/1/10
code is today.
As with subvolumes and snapshots, quotas aren't my use case or focus, but
simply knowing that they were implemented after my first trial last year,
but before raid5/6 mode in 3.9, I'd put their maturity somewhere between
as well, which would mean initial implementation is complete and in
theory they're ready for use, but there's still a LOT of debugging to go
before that can be considered stable. Quota support should therefore be
about where raid5/6 will be by the end of this year, or where raid0/1/10
were near the end of last year.
N-way mirroring (aka raid1 as many people consider it) is still on the
roadmap, as it has been, to be added after raid5/6 completion. So maybe
by the end of the year... De-dup is I believe still on the roadmap as
well.
Which means feature completion is now reasonably in sight, possibly by
end of year, and next year should be primarily stabilization, FINALLY!
It has been rather longer in coming than I think anyone expected, but
given the differences I've seen over the last year, and roadmap feature
status, next year could be the year for stabilization; the year that
experimental label finally comes off. Tho corporate production level
usage tends to be rather conservative (many have only recently switched
to ext4), so I wouldn't expect to see wide-scale deployment there until
2015 or so.
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
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