FAQ
Just wondering if anyone else has come across an issue where files
cached in memory appear to become 'corrupted' - for example, on one
workstation, I've just had the issue:

# yum
Traceback (most recent call last):
File "/usr/bin/yum", line 4, in ?
import yum
File "__init__.py", line 36, in ?
File "config.py", line 34, in ?
File "repos.py", line 29, in ?
File "repoMDObject.py", line 18, in ?

strace'ing the process didn't show up anything obvious

However, I ran a simple process that just grabs memory - which has the
side effect of 'flushing' caches from memory.

After, doing this, yum ran fine ...

I've seen this issue quite a few times with various applications and on
different machines - and flushing the caches in the way fixes the issue ...

OK, it could be a real memory problem, but given the number of times I
see this issue, on machines that are fine otherwise, it makes we wonder
if it could be a cache issue ...

All the machines are running a CentOS4.4 based kernel - (I plan to move
to a CentOS4.6 based kernel when it is out). The kernel is not a vanilla
CentOS4.4 kernel - it includes a few small non-standard patches - but
nothing that touches the VFS layer (AFAIK). The issue occurs on i686 or
x86_64 boxes. All machines have at least 4GB of memory. They also use
the nVidia binary-only module.

Anyone seen issues like this?

Thanks

James Pearson

Search Discussions

  • Dan Halbert at Dec 5, 2007 at 3:53 pm

    James Pearson wrote:
    Just wondering if anyone else has come across an issue where files
    cached in memory appear to become 'corrupted' - for example, on one
    workstation, I've just had the issue:
    There is a kernel bug for this kind of problem but it is for AMD x86_64
    only: http://bugzilla.kernel.org/show_bug.cgi?idw68 . Since you are
    reporting this for i686 as well, I'm not sure it's the same thing. The
    symptom is that an entire 4k cached file block is trashed. This was
    fixed upstream for 5.x:
    https://bugzilla.redhat.com/show_bug.cgi?id#8709. I cannot tell if a
    similar patch has gone into a 4.x kernel: the appropriate RedHat bug
    (https://bugzilla.redhat.com/show_bug.cgi?id"3238) is unfortunately
    private. Someone could look at the latest kernel sources and see.

    Dan
  • James Pearson at Dec 6, 2007 at 5:12 pm

    Dan Halbert wrote:
    James Pearson wrote:
    Just wondering if anyone else has come across an issue where files
    cached in memory appear to become 'corrupted' - for example, on one
    workstation, I've just had the issue:
    There is a kernel bug for this kind of problem but it is for AMD x86_64
    only: http://bugzilla.kernel.org/show_bug.cgi?idw68 . Since you are
    reporting this for i686 as well, I'm not sure it's the same thing. The
    symptom is that an entire 4k cached file block is trashed. This was
    fixed upstream for 5.x:
    https://bugzilla.redhat.com/show_bug.cgi?id#8709. I cannot tell if a
    similar patch has gone into a 4.x kernel: the appropriate RedHat bug
    (https://bugzilla.redhat.com/show_bug.cgi?id"3238) is unfortunately
    private. Someone could look at the latest kernel sources and see.
    Thanks for the info - the machine I recently noticed this 'yum' issue is
    a Supermicro X5DA8 with 2 x 3Ghz (32 bit) Xeons - so not a AMD x86_64
    issue - as that kernel bugzilla issue seems to be about ...

    Anyway, I'll keep poking about ...

    Thanks

    James Pearson

Related Discussions

Discussion Navigation
viewthread | post
Discussion Overview
groupcentos @
categoriescentos
postedDec 5, '07 at 3:42p
activeDec 6, '07 at 5:12p
posts3
users2
websitecentos.org
irc#centos

2 users in discussion

James Pearson: 2 posts Dan Halbert: 1 post

People

Translate

site design / logo © 2022 Grokbase