[Beowulf] Node Drop-Off

Tony Ladd ladd at che.ufl.edu
Mon Dec 4 07:35:29 PST 2006


Our university HPC cluster had similar problems with dual-core opterons
275's. They had about 20 bad ones out of a batch of 400. The nodes would run
OK for a while and then die. It took many months to track down the source of
the problem-AMD gave the same lame excuse-bad QA.


-----Original Message-----
From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On
Behalf Of Tim Moore
Sent: Monday, December 04, 2006 10:16 AM
To: beowulf at beowulf.org
Subject: Re: [Beowulf] Node Drop-Off

Update to node drop-off:

I wrote a few weeks ago to ask about node drop-off.  A quick note...I 
had a cluster run for 3 years without failure and I upgraded the Opteron 
240 CPUs to 250s.  The upgrade required a BIOS upgrade and while I was 
at it, upgraded the OS and security.  Some readers provided good 
suggestions for diagnosis.  As it turned out, of the 16 CPU batch...two 
were flawed.  No success was derived from replacing power supplies, HDD, 
resetting memory and the cooling solution.  The CPU flaw only manifested 
itself (at first) after several hours of CPU usage.  With each failure, 
the time duration shortened before the next failure and by the time I 
figured it out was down to about 2 minutes.

The AMD engineer with whom I talked was amazed that such CPUs made it 
beyond quality control.  He also suggested that the vendor may have 
inadvertently mixed returned (previously fetermined to be flawed 
processors) with the new ones and sent them out (again) as new.

Just for future reference...is there an easy way to determine if a CPU 
is flawed with 2 weeks of down time and extensive hair extraction????


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