[Beowulf] What services do you run on your cluster nodes?

[Gerry Creager]

Eric Thibodeau wrote:
> Prentice Bisbal wrote:
>> The more services you run on your cluster node (gmond, sendmail, etc.)
>> the less performance is available for number crunching, but at the same
>> time, administration difficulty increases. For example, if you turn off
>> postfix/sendmail, you'll no longer get automated e-mails from your
>> system to alert you to a problem.
>>
>> My question is this: how extreme do you go in disabling non-essential
>> services on your cluster nodes? Do you turn off *everything* that's not
>> absolutely necessary, do you leave somethings running to make
>> administration easier?
>>   
> Everything is turned off and, most of the time, a quick glance at 
> ganglia brings out problems. Simple scripts can be built to perform 
> cyclic checks on the nodes and would be less disruptive IMHO.
>> I'm curious to see how everyone else has their cluster(s) configured.
>>   
> The only actual research I found on OS interference impacting HPC 
> computing is titled "A measurement and simulation methodology for 
> parallel computing performance studies" by Matthew Joseph Sottile. I 
> would be curious to know if anyone else has dipped into the subject and 
> come up with conclusive results on the subject.

As a slightly OT question: I've recently heard it posited that ganglia 
induces severe communications overhead ("It's chatty") and thus 
shouldn't be used.  What's the conventional wisdom thereof?
-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University
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