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IOWAIT problems

Discussion in 'General Discussion' started by HostOrbit, Aug 31, 2004.

  1. HostOrbit

    HostOrbit Member

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    Hi,

    IOWAIT on our server seems to be using up a lot of resources. I have checked "top" and there doesn't seem to be any processes using up the resources.
    However, when we have this problem, it can be temporaily resolved by restarting MySQL most of the time.

    Does anyone know what the cause could be? ServerMatrix doesn't think it is the 2.4x kernel. They think it is because of traffic, but this server isn't that busy and it has 2GB of RAM which should be plenty.

    Server spec:

    RedHat Enterprise Linux
    Intel Dual Xeon 2.4GHz
    2GB DDRAM
    2X 80GB ATA/100 Drives

    Thanks in advance. :)
     
  2. chirpy

    chirpy Well-Known Member

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    Go on, have a guess
    Exactly which kernel are you running?

    uname -r
     
  3. HostOrbit

    HostOrbit Member

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    Hi,

    We are using 2.4.21-15.0.4.ELsmp on this server that has the problems.
     
  4. chirpy

    chirpy Well-Known Member

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    SM are right in that OS should be OK. However, to be sure, you can do the following (if it's not already be done anyway):

    Code:
    echo 100 > /proc/sys/vm/inactive_clean_percent
    echo 2 10 20 > /proc/sys/vm/pagecache
    Then watch your IOWAIT and see if improves. If not, it didn't help ;) If it does, then you can put both of those lines at the bottom of /etc/rc.d/rc.local so that they're run whenever the server is rebooted.
     
  5. HostOrbit

    HostOrbit Member

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    Hmm, well we appear to be having the same problem mentioned in this thread:
    http://forums.cpanel.net/showthread.php?t=21372&page=1&highlight=iowait

    Most of them had their server issues resolved by upgrading to the 2.6 kernel.
    I will try what you suggested though.

    Thanks.
     
    #5 HostOrbit, Aug 31, 2004
    Last edited: Aug 31, 2004
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