Dell PE2950 - 16GB RAM - RHEL4 ES U4 - 2.6.9-5.ELsmp system freeze

[Shannon Skerritt]

Hi all,

Recently a client of mine has experienced a server freeze. The server
is a new Dell PE2950 running RHEL4 ES U4 which is the 2.6.9-5.ELsmp
kernel with 16GB of RAM.

This server was delivered a few months ago, and on delivery but before
production it was noted there may have been a memory problem as the
server posted (booted) with less than 16GB of RAM.

Reseating the DIMMs and running mpmemory diags (a Dell utility) did
not find a problem so it was suspected the problem was possibly due
movement in system transit to the customer.

More recently, the server has completely frozen (no response to ping)
or network connectivity and no access via the local console KVM - X
was also frozen. Upon a hard reboot, examination of the system logs
and key services (SAMBA, NFS) revealed nothing at all, the absence of
which is starting to make me think of the previously suspected memory
issue. It is not believed that the server was not under considerable
load at the time. Re-running mpmemory and the Dell server diagnostics
has again revealed nothing to date.

Dell have advised the kernel (2.6.9-5.ELsmp) is quite old and there
have been (via Red Hat Network) many VM/memory issues addressed in
later kernels, the latest of which I can see is effectively RHEL 4 ES
U5 which is 2.6.9-55.ELsmp. They have recommended a kernel upgrade.

Can anyone knowledgeable or with experience comment on which direction
I should be considering? The server in question is a key file server
which is in production.

Is (RHEL 4 ES U4) 2.6.9-5.ELsmp considered particularly old or
problematic and can anyone comment if there are significant known
issues which have been addressed? I have looked at the kernel change
logs and there appears to be reference to at least a couple.

Regards,
Shannon.

-- 
Shannon Skerritt
Thousand Hill Services Limited
Email: shannon at thousandhillservices.com