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If you have like... 10 cores... and you use Apache and your load average is always under 5.0...

Would it slow your site any if you lowered to 6 cores?

(assuming you never reached any spikes that hit 6.0 in load)

Specs: Xen, 10 Cores at 2.0GHz, CentOS 5 64bit, using "uptime" to find load averages.

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closed as not a real question by womble, mgorven, Ward, Lucas Kauffman, rnxrx Aug 23 '12 at 16:55

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.


The problem is that the load average is exactly that -- an average. Sure, over the course of a minute you never got above 5 processes in the run queue, but what about in a particular second or so? You might have big spikes and just never know it. If you don't care about small latency spikes, you might get away with it.

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@dav this is the main point - a 1-minute load average of 5 might be a constant, continuous load of five threads saturating five cores, but it might also be 10 threads saturating 10 cores for half a minute and idling for the other half. In the latter case, halving the number of cores would increase response times for your users by the factor of 2. – the-wabbit Jul 1 '12 at 10:48

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