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On a fairly busy RHEL6 server I keep noticing on average following indications

CPU Usage   : 2%.
CPU Load AVG: 0.4,0.2,0.1
Memory Usage: 1.3 out of 16 GB

This is the CPU this server has

Intel(R) Xeon(R) CPU E31240 @ 3.30GHz, 8 cores

Does this mean server is healthy and is not under heavy load? I would assume so but since this is always on a low end even with fairly heavy traffic I am just wondering if I could be overlooking something?

Not that I expect the server to bog down, we try to ensure we use minimal resources and serve the web pages as efficiently as possible but I just want to make sure I'm not taken for a surprise someday.

  • Just based on that? No. Low load/RAM use could mean your important processes crashed and no one's able to do anything on the server, for example. – ceejayoz May 19 '15 at 16:55
  • @ceejayoz but everything is running fine throughout the day – Hanky Panky May 19 '15 at 17:01
  • That's great. I'm just pointing out your monitoring needs to do more than check CPU/memory usage. You'll want to verify it works. – ceejayoz May 19 '15 at 17:08
  • Yep that makes sense – Hanky Panky May 19 '15 at 17:10
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Numbers you have posted look just fine. But it is hard to tell what else is going under the hood. If the server is doing fine - meaning response times are in acceptable range, no spikes or so, everything is working as expected - then stick to the golden rule "if it's working, don't mess with it".

But if you want to do some studying, there is a great template from performance engineer Brendan Gregg that describes probably most possible bottlenecks in a Linux server and commands to monitor/reveal them.

I recommend going through the slides on that page as well.

It is important as well to have continous monitoring (using something like munin), as that is the only way to find problems occuring at odd times, or very sparsely and allows you to spot trends (future problems) as well.

Edit: oh, and don't forget logs (like i just did), always check logs.

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  • Thanks @Fox, that makes a lot of sense. And thanks for the links as well – Hanky Panky May 19 '15 at 17:04
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I can come up with two different interpretations of the numbers you posted. Which of the two applies depend on your point of view:

  • This is a server which is way larger than it need to be in order to handle the load.
  • This is a server ready to handle future usage growth.

What you need to pay attention to are the things, you did not mention in your question:

  • Do you also have sufficient network bandwidth to handle future growth?
  • Is the disk storage redundant? (RAID1 or RAID6)
  • Do you have backups?
  • Do you need other redundancy to prevent outages?
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