Re: Linux 2.6.29

Jens Axboe
2009-03-25T09:39:26Z

On Tue, Mar 24 2009, Jeff Garzik wrote:
> 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.

fsync already does that, at least if you have barriers enabled on your
drive.

--
Jens Axboe