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Thread: Network performance issues

  1. #1
    Join Date
    Jun 2011
    Beans
    16

    Network performance issues

    First of all a list my system specs:

    Running a Samba Fileserver Version: 3.5.11
    Kernel: 3.0.0.16-generic

    Network card: RTL8168 Gigabit with the correct Kernel Module from Realtek

    Code:
    04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
            Subsystem: ASUSTeK Computer Inc. P8P67 and other motherboards
            Flags: bus master, fast devsel, latency 0, IRQ 43
            I/O ports at e000 [size=256]
            Memory at d0004000 (64-bit, prefetchable) [size=4K]
            Memory at d0000000 (64-bit, prefetchable) [size=16K]
            Capabilities: <access denied>
            Kernel driver in use: r8168
            Kernel modules: r8168
    Connected to a Gigabit Switch and Gigabit should be working


    Code:
    Settings for eth0:
            Supported ports: [ TP ]
            Supported link modes:   10baseT/Half 10baseT/Full
                                    100baseT/Half 100baseT/Full
                                    1000baseT/Full
            Supports auto-negotiation: Yes
            Advertised link modes:  10baseT/Half 10baseT/Full
                                    100baseT/Half 100baseT/Full
                                    1000baseT/Full
            Advertised pause frame use: Symmetric Receive-only
            Advertised auto-negotiation: Yes
            Speed: 1000Mb/s
            Duplex: Full
            Port: Twisted Pair
            PHYAD: 0
            Transceiver: internal
            Auto-negotiation: on
    Problem:

    I'm not getting the transfer speeds I used to have. In the past I could connect my laptop with a Gigabit network card to the switch and reach transfer speeds from the Samba to Windows 7 machine of 60 MB/s which seems quite normal to me. This was with a larger MTU then the standard 1500.

    However, when I now increase the MTU above 1500 the Samba fileserver cannot be reached, however an SSH session works without a problem! And, strangest of all, when I connect with laptop through the wireless I can also access the Samba server. However, the server is always connected wired.

    Now, I can only get up to 20 MB/s with the standard 1500 MTU.

    I don't have another Gigabit computer to test with. And the drivers on my Windows machine haven't changed.

    I've been searching like crazy for the past few days to find the problem here.

    Any suggestions?

  2. #2
    Join Date
    Dec 2011
    Location
    The Netherlands
    Beans
    1,093
    Distro
    Ubuntu 11.10 Oneiric Ocelot

    Re: Network performance issues

    May i see the lshw?
    Code:
    sudo lshw -C network
    "Everything that has a beginning, has an end." --an unexpectedly wise wallpaper

  3. #3
    Join Date
    Jun 2011
    Beans
    16

    Re: Network performance issues

    As Requested:

    Code:
    *-network
           description: Ethernet interface
           product: RTL8111/8168B PCI Express Gigabit Ethernet controller
           vendor: Realtek Semiconductor Co., Ltd.
           physical id: 0
           bus info: pci@0000:04:00.0
           logical name: eth0
           version: 06
           serial: f4:6d:04:6f:c7:a7
           size: 1Gbit/s
           capacity: 1Gbit/s
           width: 64 bits
           clock: 33MHz
           capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
           configuration: autonegotiation=on broadcast=yes driver=r8168 driverversion=8.028.00-NAPI duplex=full ip=192.168.2.100 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
           resources: irq:43 ioport:e000(size=256) memory:d0004000-d0004fff memory:d0000000-d0003fff

  4. #4
    Join Date
    Dec 2011
    Location
    The Netherlands
    Beans
    1,093
    Distro
    Ubuntu 11.10 Oneiric Ocelot

    Re: Network performance issues

    I'd say that either some app is using net a lot or you've got some upstream problems.
    "Everything that has a beginning, has an end." --an unexpectedly wise wallpaper

  5. #5
    Join Date
    Jun 2011
    Beans
    16

    Re: Network performance issues

    Well, Samba is the only service running when testing so I don't see which service or daemon could be hogging resources.

    Just been testing with iperf. iperf reports the same speeds but shows an mtu of 4000 (which is reported to be the max of my network card).

    However, with an mtu of 4000 I can run iperf, ssh into the server but I can't access my Samba shares over the wired connection.

    But I can't see where or why Samba could be having problems with a larger mtu?

  6. #6
    Join Date
    Mar 2008
    Location
    Presently in Bangladesh
    Beans
    278
    Distro
    Ubuntu 9.10 Karmic Koala

    Re: Network performance issues

    Check the firewall configuration. the network speed depends on firewall also. you may need to check the firewall log closely to check the unnecessary packets to be removed from the network data transaction.
    Registered Linux User# 453907

  7. #7
    Join Date
    Jun 2011
    Beans
    16

    Re: Network performance issues

    Quote Originally Posted by Vishal Agarwal View Post
    Check the firewall configuration. the network speed depends on firewall also. you may need to check the firewall log closely to check the unnecessary packets to be removed from the network data transaction.
    A worthwhile try, I disabled all firewalls in the network. Both the SPI firewall in the router and the firewall on the server; Same result.

    In the meantime I've also connected the gigabit laptop to the server directly in an attemp to cut out the router. Speeds are still the same.

    The server itself cannot be running into a hd read problem yet, hdparm shows read speeds over 1000 MB/s. Normal for the SATAII connection.

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