Linux ext3 performance (Re: fsync() takes about 0.06 second ...)

[Jeremy Rumpf]

On Thursday 12 September 2002 10:34 am, Mika Iisakkila wrote:
> Data=journal was the clear winner; copy speed with average
> size text messages (archive of this list, actually) stayed
> mostly at a nice 20+ messages per second. Kernel buffering
> actually seemed to do something useful this time, growing
> to 20-30 megabytes and the hard disk light didn't stay on
> continuously.
>
> On the brighter side, the file system of the laptop didn't get
> corrupted :-) I still don't know if data=journal is completely safe
> yet on 2.4.19, though... Anyone know for _sure_?
>
> --mika

Good deal, the same conclusions are recomended by the postfix folks at:
http://www.stahl.bau.tu-bs.de/~hildeb/postfix/ext3.shtml

One other thing I forgot earlier is disabling atime updates on the filesystem. 
That could save some additional disk activity.

As for the stability of ext3 in journal mode.....I noticed the following in 
the 2.4.20-pre changelog:

<sct at redhat.com>:
  o 2.4.20-pre4/ext3: Handle dirty buffers encountered
  o 2.4.20-pre4/ext3: Fix "buffer_jdirty" assert failure
  o 2.4.20-pre4/ext3: Fix the "dump corrupts filesystems"
  o 2.4.20-pre4/ext3: Fix buffer alias problem
  o 2.4.20-pre4/ext3: Truncate leak fix
  o 2.4.20-pre4/ext3: Fix out-of-inodes handling
  o 2.4.20-pre4/ext3: fsync optimisation
  o 2.4.20-pre4/ext3: Fix truncate restart error
  o 2.4.20-pre4/ext3: Performance fix for O_SYNC behaviour

It's probably best to ask Mr. Tweedie though for a definite answer.

Thanks for the info,
Jeremy