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High iowait

Discussion in 'General Discussion' started by netlook, Nov 24, 2004.

  1. netlook

    netlook Well-Known Member
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    What may cause very high iowait on RHE PIV 2,8HT box?

    Can you give me some tips to reduce this iowait?
    I have 2 more servers, and the load between all my servers is simillar, but I don't have iowait problems on those two, olny on HT machine.

    Please advice.
     
  2. chirpy

    chirpy Well-Known Member

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    What kernel are you running?

    uname -a

    Older RHE kernels were known to have IOWAIT issues, but the recent ones have been fixed.

    A temporary measure is to run the following and place the commands in your /etc/rc.d/rc.local so they're run again after a reboot:

    echo 100 > /proc/sys/vm/inactive_clean_percent
    echo 2 10 20 > /proc/sys/vm/pagecache
     
  3. netlook

    netlook Well-Known Member
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    2.4.21-15.0.4.ELsmp from ServerMatrix/ThePlanet
     
  4. chirpy

    chirpy Well-Known Member

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    Hi,

    That's an old kernel and you should update it. It's known to have the IOWAIT problem. The commands I posted above will help with it, though.
     
  5. challii

    challii Well-Known Member

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    anyway to easily upgrade to a new version as servermatrix seem adamanent that that version has no problems at all.

    Seems strange how when we bugged them enough they upgraded us to 2.6 on our last server and server was really stable after that.
     
  6. netlook

    netlook Well-Known Member
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    So, you think it should be updated to 2.6? Which 2.6 would be OK for my box (2,8PIV HT, 2GB RAM)?

    Thank you
     
  7. koke

    koke Registered
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  8. chirpy

    chirpy Well-Known Member

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    There's no need to go to the 2.6 kernel (and that only introduces other problems WRT keeping that up to date). The latest RHE kernel is 2.4.21-20.EL and the IOWAIT issues are resolved in that. You can install it using up2date.
     
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