MTU size for Windows 2003

Discussion in 'Server Networking' started by Sabo, Eric, Oct 3, 2007.

  1. Sabo, Eric

    Sabo, Eric Guest

    We are trying to get more speed out of our Windows 2003, currently they are
    only topping out at 230 MB per second on a CISCO 6513 switch. Should we
    use a larger size that 1514 for the MTU?

    Any thoughts would help us.

    Thanks,
    Eric Sabo
     
    Sabo, Eric, Oct 3, 2007
    #1
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  2. Hello,

    Is it Mega bits or Mega Bytes ? B in caps is normally for Bytes.

    Changing MTU will overload the switch as others machines are still in 1500.

    Do you have the latest driver ?
    Do you have Service pack 2 or the network scalable pack ?
    Do you have a teaming on your network card ? is it active/active ?
    What is the service behinds ? disk system may be the guilty one.
     
    Mathieu CHATEAU, Oct 3, 2007
    #2
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  3. Sabo, Eric

    FenderAxe Guest

    Definitely not -- some protocols and services will fail if you do this, and
    as the other poster mentioned you can overload switches, plus routers might
    drop packets.

    Are you sure the server is what's slow? The switch might be misconfigured
    somehow, especially if there has been experimentation with switch
    settings.. Test the server with other computers on the same switch
    port/LAN.

    Also test other server funtionality if possible, it might be a software
    problem, not a prob with the OS.

    FA
     
    FenderAxe, Oct 3, 2007
    #3
  4. Sabo, Eric

    Sabo, Eric Guest

    MegaBytes

    Yes - the latest drivers are being used
    Service Pack 2 is installed
    No teaming is being used

    I did a perform log file and do not see any bottlenecks on the servers.
     
    Sabo, Eric, Oct 3, 2007
    #4
  5. Sabo, Eric

    Sabo, Eric Guest

    The ports are set to 1000 and full.

    Vlan are set correctly.
     
    Sabo, Eric, Oct 3, 2007
    #5
  6. That may not be the recommended way for 1000. For example, i read an HP
    paper saying to let it to auto-1000 and i think you can't even set duplex on
    1000 ports on last HP firmware.
     
    Mathieu CHATEAU, Oct 3, 2007
    #6
  7. Hello,

    you use teaming to double the capacity.
    Are you sure client can handle more speed ?
    It may the client that slow server's speed.

    Did you change tcp windows on the server ?
    What sort of traffic is it ? http ?
     
    Mathieu CHATEAU, Oct 3, 2007
    #7
  8. Sabo, Eric

    Sabo, Eric Guest

    I know when you go into their network configuration utility it does not
    allow 1500 bytes.

    You can hard code most speeds with HP NICs.

    My question would be is how would one tell if 1514 bytes is not working or
    chopping the packets, is there anything on the server I can see.
     
    Sabo, Eric, Oct 3, 2007
    #8
  9. You seem to not have read one of my previous post:

    you can use teaming to double the bandwith.
    Are you sure your client can handle more speed ?
    It may the client that slow server's speed.

    Did you change tcp windows on the server ?
    What sort of traffic is it ? http ?
     
    Mathieu CHATEAU, Oct 3, 2007
    #9
  10. Sabo, Eric

    Sabo, Eric Guest

    I am not using teaming on any server hardware.

    No changes were made with the TCP on the server.

    file copies and backups.

    I tried connecting four clients to on server and it does not go above 100 MB
    which is 10% throughput of a gigabit adapter
     
    Sabo, Eric, Oct 3, 2007
    #10
  11. Sabo, Eric

    Anthony Guest

    bits, bytes?


     
    Anthony, Oct 3, 2007
    #11
  12. Can you disk system provide more ?
     
    Mathieu CHATEAU, Oct 3, 2007
    #12
  13. i meant can your disk system provide more ?

    You may use http://www.hdtune.com/download/
    to stress out your disks.

    Files copies ? any antivirus on server or clients ?
     
    Mathieu CHATEAU, Oct 3, 2007
    #13
  14. Sabo, Eric

    Sabo, Eric Guest

    bytes


     
    Sabo, Eric, Oct 3, 2007
    #14
  15. Sabo, Eric

    Sabo, Eric Guest

    Yes, I ran a perfmon during the copy and the servers isn't the bottleneck.
     
    Sabo, Eric, Oct 3, 2007
    #15
  16. Sabo, Eric

    Sabo, Eric Guest

    Nope, AV was disabled during my test.

    All of my servers as far as I can see cannot get speeds over 200 MB per
    second when copying data.
     
    Sabo, Eric, Oct 3, 2007
    #16
  17. If it's Bytes, 100 MB= 800 Mb. That a lot more close to 1000Mb.
     
    Mathieu CHATEAU, Oct 4, 2007
    #17
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