Re: Linux 2.6.29
[Posted March 31, 2009 by corbet]
| From: |
| Jeff Garzik <jeff-AT-garzik.org> |
| To: |
| Linus Torvalds <torvalds-AT-linux-foundation.org> |
| Subject: |
| Re: Linux 2.6.29 |
| Date: |
| Tue, 24 Mar 2009 15:55:28 -0400 |
| Message-ID: |
| <49C93AB0.6070300@garzik.org> |
| Cc: |
| Theodore Tso <tytso-AT-mit.edu>, Ingo Molnar <mingo-AT-elte.hu>,
Alan Cox <alan-AT-lxorguk.ukuu.org.uk>,
Arjan van de Ven <arjan-AT-infradead.org>,
Andrew Morton <akpm-AT-linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra-AT-chello.nl>,
Nick Piggin <npiggin-AT-suse.de>,
Jens Axboe <jens.axboe-AT-oracle.com>,
David Rees <drees76-AT-gmail.com>, Jesper Krogh <jesper-AT-krogh.cc>,
Linux Kernel Mailing List <linux-kernel-AT-vger.kernel.org> |
| Archive‑link: | |
Article |
Linus Torvalds wrote:
> But I really don't understand filesystem people who think that "fsck" is
> the important part, regardless of whether the data is valid or not. That's
> just stupid and _obviously_ bogus.
I think I can understand that point of view, at least:
More customers complain about hours-long fsck times than they do about
silent data corruption of non-fsync'd files.
> The point is, if you write your metadata earlier (say, every 5 sec) and
> the real data later (say, every 30 sec), you're actually MORE LIKELY to
> see corrupt files than if you try to write them together.
>
> And if you write your data _first_, you're never going to see corruption
> at all.
Amen.
And, personal filesystem pet peeve: please encourage proper FLUSH CACHE
use to give users the data guarantees they deserve. Linux's sync(2) and
fsync(2) (and fdatasync, etc.) should poke the block layer to guarantee
a media write.
Jeff
P.S. Overall, I am thrilled that this ext3/ext4 transition and
associated slashdotting has spurred debate over filesystem data
guarantees. This is the kind of discussion that has needed to happen
for years, IMO.
