Understanding Linux CPU Load – when should you be worried?
You might be familiar with Linux load averages already. Load averages are the three numbers shown with the uptime and top commands – they look like this:
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Most people have an inkling of what the load averages mean: the three numbers represent averages over progressively longer periods of time (one, five, and fifteen minute averages), and that lower numbers are better. Higher numbers represent a problem or an overloaded machine. But, what’s the the threshold? What constitutes «good» and «bad» load average values? When should you be concerned over a load average value, and when should you scramble to fix it ASAP?
Most people have an inkling of what the load averages mean: the three numbers represent averages over progressively longer periods of time (one, five, and fifteen minute averages), and that lower numbers are better. Higher numbers represent a problem or an overloaded machine. But, what’s the the threshold? What constitutes «good» and «bad» load average values? When should you be concerned over a load average value, and when should you scramble to fix it ASAP?
First, a little background on what the load average values mean. We’ll start out with the simplest case: a machine with one single-core processor.
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