Move to another server?

John Wade jwade at
Fri Jan 21 22:53:19 EST 2005

Hi Sebastian

Here are the RHEL versions we have used:

vmlinux-2.4.21-15.0.4.ELsmp  - good
vmlinux-2.4.21-20.ELsmp - bad
vmlinux-2.4.21-27.0.1.ELsmp - good

2.4.21-20.ELsmp has a bug with file system caching of very large numbers 
of files.  (generally only occurs with more than 3-4GB of RAM and lots 
and lots of small files as in cyrus)  See

This appears to be fixed in the latest (2.4.21-27.0.1 kernel)

Hope this helps,

Sebastian Hagedorn wrote:

> Hi,
> --On 29. Dezember 2004 5:26:06 Uhr -0600 John Wade <jwade at> 
> wrote:
>> One other thing to note, if you are using RHEL 3, be sure to get the
>> latest kernel.   There was a bug in the file system caching code in the
>> update 3 that kills any heavily used system with large amounts of memory
>> (like our server) and lots of small files (like cyrus)   This showed up
>> in our conversion testing and we had to backrev the kernel until the new
>> one was released.
> could you please specify the exact kernel versions you are referring 
> to? I'm not sure which version update 3 was. We are currently running 
> 2.4.21-15.0.3.ELsmp. We can't really use a newer version, because we 
> need IBM's sdd driver for SAN vpaths and they are slow in certifying 
> new kernels ... maybe telling them about specific issues might speed 
> up the process.
> We haven't really had problems like the ones you are describing, but 
> we have one where the loopback interface gets stuck. All RedHat has to 
> say about that is to try the most recent kernel, of course.
> Thanks, Sebastian Hagedorn
> -- 
> Sebastian Hagedorn M.A. - RZKR-R1 (Gebäude 52), Zimmer 18
> Zentrum für angewandte Informatik - Universitätsweiter Service RRZK
> Universität zu Köln / Cologne University - Tel. +49-221-478-5587

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