Re: 20050510: computer freezes

• To: Arthur A. Person
• Subject: Re: 20050510: computer freezes
• From: owner-gembud@xxxxxxxxxxxxxxxx
• Date: Wed, 11 May 2005 11:57:14 -0500

Do you have dual CPU's or a single CPU on this machine?  Your top output shows 
two CPUs.

I have a dual Xeon system that works great when hyperthreading is enabled (top 
output shows 4 virtual CPUs) but when a new kernel loaded them without their 
"sibling", meaning no hyperthreading (top output shows two CPUs), performance 
was severely degraded.  So I "downgraded" to an earlier kernel that would load 
them as 4 virtual CPUs, and the machine runs fine.

Also, if this machine is a NFS server, try unmounting all the NFS clients and 
see if there is still a problem.

Random freezes could also point to a bad or overheated CPU.

Patrick

On Wed, 11 May 2005, Gabe Langbaue wrote:
>Okay, the whole story goes like this...we had an old sun system that ran
>these scripts.  When I started taking care of it in September, it was
>obvious that this system was too old and decrepit to continue.  Luckily, I
>was able to convince the powers that be that a new system was needed.  The
>new system came in December, and we transfered all scripts and updated
>GEMPAK and LDM to the new versions.  The system worked fine from about
>Christmas until maybe a month ago.  Around this time I added a couple
>scripts (model differences).  When the crashes started occuring, my
>immediate thought was an error with one of the new scripts.  Therefore, I
>disabled all of them, to no avail.  I then looked and found a java script
>that had stopped working and thought that was the problem.  I disbaled it
>and found no change in performance.
>
>It appears to me that the crashes occur randomly.  At different times of
>the day and after very different uptimes.  Sometimes we're up for a week,
>sometimes (like yesterday) 3 crashes in a single day.  Therefore, I
>conclude that if it is a single script, it's one that runs at least
>hourly.  I've made a list of all of these scripts and am now disabling
>them one by one to see if I get any results.

• References:
  • Re: 20050510: computer freezes
    • From: Gabe Langbauer