2 Replies Latest reply on Jul 29, 2014 3:43 PM by 967253

    How to enable jumbo frames on a SPARC T4-1

    967253

      T4-1 current setting is mtu=1500, I want to use jumbo frames, mtu=9000, the attached network devices are set-up for 9000, so no issue there.

       

      This server also has several LDOMs running on it, they are also at 1500 and I want them to be 9000.

       

      Questions

       

      1.     Is it possible to enable jumbo frames on the T4 without a reboot?
      2.     Will the LDOMs automatically pick the new setting - or do I need to go to each LDOM and set it there?
      3.     If a reboot is required, what is the best order to do things in, for example, set the mtu in each of LDOMs, then the host, then reboot?
      4.     If I set the T4 to jumbo frames, do I still need to set the mtu for the virtual switches? For example ldm set-vsw mtu=9000 primary-vsw0, or will they change automatically?

       

      root@t4:/kernel/drv# dladm show-phys

       

      LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE

       

      net1              Ethernet             up         1000   full      igb1

       

      net7              Ethernet             up         1000   full      nxge3

       

      net5              Ethernet             up         1000   full      nxge1

       

      net3              Ethernet             up         1000   full      igb3

       

      net6              Ethernet             up         1000   full      nxge2

       

      net0              Ethernet             up         1000   full      igb0

       

      net4              Ethernet             up         1000   full      nxge0

       

      net2              Ethernet             up         1000   full      igb2

       

      net9              Ethernet             up         10     full      usbecm2

       

      net10             Ethernet             up         1000   full      vsw2

       

      net11             Ethernet             up         1000   full      vsw3

       

      net12             Ethernet             up         1000   full      vsw1

       

      net25             Ethernet             up         1000   full      vsw4

       

      net13             Ethernet             up         1000   full      vsw5

       

      net8              Ethernet             up         1000   full      vsw0

       

      net14             Ethernet             up         0      unknown   vsw6

       

      net15             Ethernet             up         0      unknown   vsw7

       

      Sample

       

      root@t4:/kernel/drv# dladm show-linkprop -p mtu net1

       

      LINK     PROPERTY        PERM VALUE          DEFAULT        POSSIBLE

       

      net1     mtu             rw   1500           1500           60-9216

        • 1. Re: How to enable jumbo frames on a SPARC T4-1
          Ppiwonski-Oracle

          Hi,

           

          To enable Jumbo Frame on a vsw and vnet the Jumbo Frame needs to be enabled within a driver of a underlying device. If this is not enabled then a change in conf file of driver and reboot is required. If this was enabled then you need to change the mtu of a specific vsw as described in document:

          http://docs.oracle.com/cd/E19227-01/820-7253/configurevnetvswitchjumboframetask/index.html

           

          "Enable jumbo frames on an existing virtual switch device in the service domain by specifying its MTU as a value of the mtu property

          # ldm set-vsw mtu=value vswitch-name

          In addition to configuring the virtual switch, this command updates the MTU value of each virtual network device that will be bound to this virtual switch."

           

          I'm not sure if the existing vnet will be updated but in case this will be not done you can change this via ldm set-vnet command.

           

          When this will be done then simple:

          dladm set-linkprop -p mtu=9000 <device_name>

           

          should change the mtu to jumbo frame on a specific vnet.

           

          Regards,

          Peter

          1 person found this helpful
          • 2. Re: How to enable jumbo frames on a SPARC T4-1
            967253

            Thanks  Peter.

             

            It was the line "In addition to configuring the virtual switch, this command updates the MTU value of each virtual network device that will be bound to this virtual switch."

            which was getting me thinking that it may update the attached vnet's. I'll think I'll set the LDOMs, then the vsw and then reboot.