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Thread: Lunix Network tuning between SuSE versions

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  1. #1

    Lunix Network tuning between SuSE versions

    We have a SLES 11.2 box and another box running SLES 11.1 here in Akron.

    We have a box in Luxembourg running SLES 11.1 and another running 11.2 (was a SLES 10.2 machine but has been temporarily replaced with the 11.2 one).

    I can transfer files from Lux to Akron from either of the Lux machines to either of the Akron machines and I get nearly the full capability of the pipe (100 Mbps).

    But I can't transfer the same files from Akron to Lux at that same speed.


    Akron 11.2 to Lux 11.2 = 74 Mpbs
    Akron 11.2 to Lux 11.1 = 50 Mpbs

    Akron 11.1 to Lux 11.2 = 27 Mpbs
    Akron 11.1 to Lux 11.1 = 37 Mpbs

    All Lux to Akron combinations get > 85 Mbps consistently. We really need all these combinations to work properly both directions.

    I have looked at all parameters the internet says matters to transfer performance, but to no avail.

    I don't know if this is a sending limitation or a receiving problem. Our network guys say the pipe itself is fine.

    So anyone have ideas of what to set on which machine to bring the rate from Akron to Lux up?

    Thanks for any info.


    PS: Akron 11.2 = 3.0.13-0.27-default kernal
    11.1 =

    Lux 11.1 =
    11.2 = 3.0.34-0.7-default

  2. #2
    ab NNTP User

    Re: Lunix Network tuning between SuSE versions

    Hash: SHA1

    Transfer them how? Have you tried other sources/destinations at the
    same sites? At different sites?

    Good luck.
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    Comment: Using GnuPG with Mozilla -

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  3. #3

    Re: Lunix Network tuning between SuSE versions

    we have this fast connection only to these 4 boxes.
    so i can't go to any other boxes...

  4. Re: Lunix Network tuning between SuSE versions

    Quote Originally Posted by twurgler
    we have this fast connection only to these 4 boxes.
    so i can't go to any other boxes...

    Are all the network interfaces using the exact same device driver? On
    each system post the output from (Please use code tags for the output);

    ethtool ethX
    hwinfo --netcard
    Are they all going through the same switches on the routes to/from the

    Cheers Malcolm °¿° (Linux Counter #276890)
    SUSE Linux Enterprise Desktop 11 (x86_64) Kernel 3.0.34-0.7-default
    up 10 days 16:44, 2 users, load average: 0.45, 0.36, 0.36
    CPU Intel i5 CPU M520@2.40GHz | Intel Arrandale GPU

  5. #5

    Re: Lunix Network tuning between SuSE versions

    reread your note.

    I was using scp. this does work fast from Lux to here. but then started using
    rsync --compress --rsh=rsh ......

    this is faster, but still faster from Lux than to Lux.

  6. Re: Lunix Network tuning between SuSE versions

    Hi Tom,

    to rule out session initiation problems: are those transfers of sufficiently large files, taking more than a few seconds? (I'm thinking of delays when i.e. the Lux receiver host waits while unsuccessfully trying to resolve the DNS name of the remote host.)

    Another probable cause might be differences in TCP window sizes or in max IP packet sizes - those would be things that the networkers might be able to check.

    If the transfer takes long enough (minutes?) it might be interesting to monitor the bandwidth use across the whole copy process - i.e. do you ever get the same max load as in the other direction? Do you get a constant load or is something "stepping on the link" during the transfer? One more thing to check is the actual load on the link - is it fully loaded, despite the slow netto speed seen with the transfer?

    A last thing that comes to mind is actual asymmetric bandwidth at the link level: If (for whatever reason) the available bandwidth towards Lux is lower than when sending from Lux, then you'd see this type of behaviour, too.


  7. #7
    Join Date
    Feb 2012
    Wescosville, Pa, USA, North America, Earth, Sol, Gould Belt, Orion-Cygnus Arm, The Milky Way, ...

    Re: Lunix Network tuning between SuSE versions

    Toss wireshark on ( any of these boxes ) and do your transfer. You can deduce which is slow, how big the window size is, fragmentation, ..... and "all parameters the internet says matters to transfer performance." You may find retransmissions, or whatever. Some times the issue will be in the poor selection of MTU's, which can be an issue with ICMP is filtered. But thats the first step... observe what is actually happening on the wire.

    -- Bob

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