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Impact of CPU and IO

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  • Impact of CPU and IO


    I have a dedicated server with:
    - CPU E3-1230 V2 @ 3.30GHz
    - 32GB Memory
    - 2TB Hard Disk

    On normal basis 10-20 websites are actively opened. Most of the websites are WordPress with not much traffic/load.

    My current LVE settings are:
    Speed: 80%
    vMem: 0
    pMem: 512MB
    EP: 20
    nProc: 100
    I/O: 1024Kbps
    IOPS: 1024

    Heres my current Disk Usage Stat:
    The CPU load average is normally: 2.31 1.52 1.45

    A few of my client websites are hitting 2 limits on Daily basis:
    - CPU Faults
    - IO Faults

    Physical memory is never exceeded.

    I need some suggestions:

    - If I increase my Speed to 100%, will it affect other services running on server? Like cPanel daemons, EXIM and R1Soft backup? As many of my clients are using emails and many emails are bounced daily.
    - Should I give more I/O to everyone? Something like 2048KBps? But My concern is if too many I/O input might crash the server.

    Any suggestions are much appreciated.


  • #2

    1. Recommended value for CPU speed limit is 100% , means one full core. That is system default and will works great. It will not cause any issues for R1Soft or system services.

    2. There are situations when default IO limits are not enough, this could happen when websites are storing large files to download/upload etc. Or, when some plugins are doing backups from wordpress. You should review what accounts are hitting IO limits. However, I am sure it is safe to increase it to 2048 for everyone.

    Overall, please review our webinar about optimizing CloudLinux OS limits:


    • #3
      Hi Bogdan, Thanks a lot for such useful information. Really appreciated The video was very useful as well. Today I changed the settings, Speed to 100% and IO to 2048. The server started crashing. Then I switched Speed back to 80%. Now the server is running much smooth and the Disk Usage has drastically reduced. Here is current status: Now, CPU is what I am confused about. Can you please explain if I set CPU to 100%, I understand its 100% of 1 core. But my CPU has 8 Cores. If I set to 100%, doesnt it mean the websites can use all 8 cores to 100% each? If thats the case, then I presume thats why my server crashed for setting it to 100%. Any more clarification will be helpful. Thanks


      • #4
        Before suggesting changing CPU SPEED to 100% I checked CPU model specifications that is is multicure (number of cores=4, number of threads=8).

        Yes, setting SPEED to 100% means that LVE can use 1 full core. Not 100% of each. But, how it was crashing?


        • #5
          Was getting Connection Timed Out on a website hosted on this server. Even WHM was not working proper, each time I clicked some link it crashed. Then it was a bit of headache to get it back to 80% and everything started working normally.

          Here are the current Service Status on my WHM:


          • #6
            Pretty strange.

            We would like to check your server to be sure everything is configured properly. Please create support ticket at .


            • #7

              Thanks a lot. I again faced a few downtime issues today morning and upon discussion with my server provider, they suggested us to Upgrade to Dual CPU E5 server, so I have opted to it.

              They have already started working on it. If I face any issue again, I will surely create a ticket with you.

              Thanks a lot!