lkml.org 
[lkml]   [2010]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 2.6.36 io bring the system to its knees
On Sun, Nov 07, 2010 at 07:50:13AM -0800, Linus Torvalds wrote:
> On Sun, Nov 7, 2010 at 4:08 AM, Jens Axboe <axboe@kernel.dk> wrote:
> >
> > As already mentioned, ext3 is just not a good choice for this sort of
> > thing. Did you have atimes enabled?
>
> At least for ext3, more important than atimes is the "data=writeback"
> setting. Especially since our atime default is sane these days (ie if
> you don't specify anything, we end up using 'relatime').
>
> If you compile your own kernel, answer "N" to the question
>
> Default to 'data=ordered' in ext3?
>
> at config time (CONFIG_EXT3_DEFAULTS_TO_ORDERED), or you can make sure
> "data=writeback" is in the fstab (but I don't think everything honors
> it for the root filesystem).

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*. Not to mention
the significant security issues (e.g stale data exposure) that also
occur even if the filesystem is not corrupted by the crash. IOWs,
data=writeback is the "fast but I'll eat your data" option for ext3.

So I recommend that nobody follows this path because it only leads
to worse trouble down the road. Your best bet it to migrate away
from ext3 to a filesystem that doesn't have such inherent ordering
problems like ext4 or XFS....

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com


\
 
 \ /
  Last update: 2010-11-10 02:37    [W:0.081 / U:0.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site