Re: 2.6.36 io bring the system to its knees

[Dave Chinner]

On Wed, Nov 10, 2010 at 07:59:10AM -0800, Linus Torvalds wrote:
> On Tue, Nov 9, 2010 at 5:32 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> >
> > Don't forget to mention data=writeback is not the default because if
> > your system crashes or you lose power running in this mode it will
> > *CORRUPT YOUR FILESYSTEM* and you *WILL LOSE DATA*.
> 
> You will lose data even with data=ordered. All the data that didn't
> get logged before the crash is lost anyway.
> 
> So your argument is kind of dishonest. The thing is, if you have a
> crash or power outage or whatever, the only data you can really rely
> on is always going to be the data that you fsync'ed before the crash.
> Everything else is just gravy.

I crash kernels tens of times every day doing filesystem testing.
With data=ordered I have not seen a corrupted root filesystem as a
result of normal testing and crashing as long as I can remember.
With data=writeback, I'll have corrupted root ext3 partitions in
under a day. Hardly what I'd call stable or something you'd want
to deploy in production.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
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