Re: [2.3.99pre2] [CORRUPTION] Doh! Corruption problems again...

From: Simon Kirby (sim@stormix.com)
Date: Tue Mar 21 2000 - 12:29:18 EST


Woops, sent that last email too early. :)

On Tue, Mar 21, 2000 at 08:37:53AM -0800, Simon Kirby wrote:

> - hdparm -u 1 vs hdparm -u 0 on all drives does not seem to make a
> difference.
>
> - hdparm -d 0 vs hdparm -d 1 on all drives tends to make the problem
> happen even more often (guessing 5 times as often). Tested with
> both -u 1 and -u 0.

- Memory pressure does not appear to affect the problem.

- Booting "nosmp" seems to make the problem disappear (the problem seems
  to be SMP specific).

- The problem only seems to happen when copying files between drives
  (copying on the same filesystem does not seem to reproduce it).

- The problem does not seem to occur when copying files from one drive
  to another on the same IDE bus. This may be a coincidence of my setup,
  however -- I only have hda, hdb, and hdc, an hdc contains only 1K block
  EXT2 filesystems. hda and hdb contain 2K and 4K filesystems.

The problem occurs when copying from /dev/hdc2 (1K EXT2 filesystem) to
/dev/hdb1 (2K EXT2 filesystem). I haven't been able to reproduce it
copying from hda4 (4K) to hdb2 (2K). I also haven't been able to
reproduce it copying from hda4 (4K) to hdc2 (1K). I'm not sure if this
is a result of the direction of the copying or an indication of a
filesystem blocksize dependency.

I just reproduced it copying in the exact opposite direction (/dev/hdb1
to /dev/hdc2) from the original way I reproduced it. This is from a 2K
to a 1K. Aha! I just reproduced it going from /dev/hdb4 (4K) to /dev/hdc2
(1K), so the source blocksize does not seem to matter. I should see if I
can reformat hdc to have a 4K filesystem, I suppose... Although I'm
getting the feeling the problem might be completely independent of block
size...

So, SMP definitely makes a difference and IDE bus definitely makes a
difference.

Simon-

[ Stormix Technologies Inc. ][ NetNation Communcations Inc. ]
[ sim@stormix.com ][ sim@netnation.com ]
[ Opinions expressed are not necessarily those of my employers. ]

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