How to check server load and what is a good load?

Discussion in 'Hosting Discussions' started by Agurus, Aug 28, 2008.

  1. Agurus

    Agurus Aspirant

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    How do i check server load and what is a good load?

    I am on a linux server with SSH access ( i think it was TOP but I dont know how to read it)
     
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  2. motokochan

    motokochan Habitué

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    You can use the "uptime" command. This will give you both the length since the last reboot, and the three load averages. These are calculated for 1, 5, and 15 minutes.

    The ideal load would be below 1, but that usually doesn't happen on a busy server. My general rule is that if the server is running smoothly then the load is fine. A single-processor server can hit a load of 10 easily with no noticeable slowdown on its primary task. I've seen a server go above 25 in use with minimal issues (it was a mail server and got hit with a large newsletter) except some lag at the shell.

    The more important thing to watch is the swap usage. The "free" command will show memory usage. The more swap that is used, the more likely there isn't enough system memory in the server. If the swap usage grows significantly over time, then it is a big signal that more memory is needed in the server, or the load on it needs to be lightened.
     
  3. Agurus

    Agurus Aspirant

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    Hi here is my swap info (total, used, free):

    Swap: 2048276 26192 2022084

    Does that look good?

    I have 1gb on my dedi server
     
  4. dwykofka

    dwykofka Participant

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    As stated by Motokochan the uptime command is a much better indication of actual server load

    Everyone will tell you that acceptable server loads are different for different boxes and this is largely true however it's fairly obvious that lower is better, I will post some load levels from a few of my production web hosting servers so that you can judge for yourself.

    [root@xx11 ~]# uptime
    12:56:47 up 81 days, 17 min, 1 user, load average: 0.37, 0.30, 0.24

    [root@xx12 ~]# uptime
    12:58:20 up 33 days, 17:17, 1 user, load average: 0.58, 0.47, 0.45

    [root@xx13 ~]# uptime
    12:59:00 up 53 days, 10:42, 1 user, load average: 0.34, 0.39, 0.35

    You can see that all of the above servers average a load of less than .5 which is a great load level. Each one of the servers listed has over 300 websites hosted.

    Now keep in mind we provide very high end hosting as compared to some of these walmart hosting companies that are saturating the market so other people's opinion of an acceptable load might be different.
     
  5. motokochan

    motokochan Habitué

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    Since we are showing sample loads, here are a few from the servers I manage. My day job is a server admin for a small web development company. We also happen to do hosting, mostly for the projects we code.

    Our main shared server:
    11:51:59 up 193 days, 11:55, 1 user, load average: 0.00, 0.00, 0.00

    It has about 100 sites on it. It runs on a single 2.78gHz Xeon with 1gB RAM.

    Our big dedicated applications server:
    11:53:16 up 130 days, 22:11, 1 user, load average: 1.05, 0.98, 0.89

    This is a dedicated server simply for one customer. It runs a system we coded that acts as a templated site system for the promotional products industry. Basically, the customer sells pre-fabricated sites that use the system. There are currently over 1,000 sites handled by that system. A lot of image processing is done (the imagemagick calls alone are rather amazing), so there was the need for some hefty hardware. It runs on four dual-core 2.2gHz Opteron processors and has 4gB of memory.

    Note that neither of these servers has a local SQL server sitting on them, that's a different box.
     
  6. Secure

    Secure Adherent

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    Are the sample loads only available on linux dedicated hosts?
     
  7. dwykofka

    dwykofka Participant

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    Yes, On a windows server you can just check the performance monitor
     
  8. Baldilocks

    Baldilocks Fanatic

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    My current server load averages:

    0.16 0.11 0.17 | 181 Users Online (30 members and 151 guests)

    (URLJet VPS)

    Usually (with a vBulletin forum anyway) you can start to see the difference when those loads go above 2.0.