North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: Quick question.

  • From: Paul Jakma
  • Date: Thu Aug 05 01:56:03 2004

On Wed, 4 Aug 2004, Alexei Roudnev wrote:

I am sorry, but I do not make a theory - I just repors practical results. 2 CPU systems are much more stable than 1 CPU system, in my experience. You are free to find an explanatiion, if you want -:).
The theory suggests your experience is unusual, or that you're overemphasising one positive contributor towards system reliability of complexity against the negative impacts of complexity.

Again, I'm not arguing that the more complex system (eg SMP) must always be more unreliable, a well-engineered complex system will be more reliable than a simple but badly-engineered system. I know of an SMP PC server that hit at least 4 years uptime (never rebooted while i was in the employ of that company anyway ;) ), however it would have been just as reliable with just one CPU. And for a large sample of those machines, identical other than single and dual CPU, the set of single CPU machines will be statistically more reliable. Further, for a diverse sample of hardware of varying quality, you will see far more problems with SMP systems - primarily due to software (eg drivers with subtle locking bugs).

Nor am I arguing that the tradeoff of reliability for better performance is unwise, particularly since in this case (SMP systems), CPU failures tend to be rare (unless secondary due to some other failure, eg cooling).

anyway, I'm repeating myself, so i'll stop before susan larts me, and let the list get back to its favoured topic of discussing analogies. ;)

regards,
--
Paul Jakma [email protected] [email protected] Key ID: 64A2FF6A
Fortune:
You're working under a slight handicap. You happen to be human.