Jumbo Frames !!!!!!

-> Lets understand what’s Jumbo Frames first and how it benefits us …

  • Jumbo frames are Ethernet frames with more than 1,500 bytes of payload (MTU). Conventionally, jumbo frames can carry up to 9,000 bytes of payload.

  • Jumbo Frames allow ESX Server to send larger frames out onto the physical network. The network must support Jumbo Frames end‐to‐end for Jumbo Frames to be effective.

  • iSCSI with jumbo frames gives better or rather much better performance .If you are getting sluggish performance then try enabling jumbo frames

So let’s activate it, I have used Jumbo frames only with SW initiator not HW one so if some can comment on how it works on HW it would be in for a great benefit.

Most probably you might have your VMkernel setup with 1500 MTU so we need to delete it and start over again. Its recommend to start from 0 but if you wish you can enable the jumbo frames on the fly, it won’t throw any errors.

In my case vSwitch1 was used as VMkernel for iscsi.

Step  1: [root@esx sysconfig]# esxcfg-vswitch -d vSwitch1 Step 2:

Then I went ahead and did a listing

[root@esx sysconfig]# esxcfg-vswitch -l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0

PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0

As it can be seen no VMkernel

Then lets start the stuff ………

Step 3:

Add a vSwitch

[root@esx sysconfig]#  esxcfg-vswitch -a vSwitch1 Step 4:

List it…. [root@esx sysconfig]#  esxcfg-vswitch -l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0 PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0 Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch1       64          1           64                1500 PortGroup Name      VLAN ID  Used Ports  Uplinks

Step 5: Lets set the jumbo frames AKA MTU

If you wish you can execute the below command on the fly to your vSwitch without deleting it[root@esx sysconfig]# esxcfg-vswitch -m 9000 vSwitch1 List it to see the diference [root@esx sysconfig]#  esxcfg-vswitch -l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0 PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0 Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch1       64          1           64                9000 PortGroup Name      VLAN ID  Used Ports  Uplinks As it can be seen MTU is now 9000 not 1500

Step 6 : Lets assign a NIC to the newly created vSwitch [root@esx sysconfig]# esxcfg-vswitch -L vmnic1 vSwitch1 The result [root@esx sysconfig]# esxcfg-vswitch - l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0 PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0 Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch1       64          2           64                9000    vmnic1 PortGroup Name      VLAN ID  Used Ports  Uplinks Step 7: Lets give it a port group [root@esx sysconfig]#  esxcfg-vswitch -A VMkernel vSwitch1 Step 8:

Lets see Whether we got desired output [root@esx sysconfig]#  esxcfg-vswitch -l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0 PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0 Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch1       64          2           64                9000    vmnic1 PortGroup Name      VLAN ID  Used Ports  Uplinks VMkernel            0        0           vmnic1 Step 9:

Now lets give it IP [root@esx sysconfig]#  esxcfg-vmknic -a -i 192.168.0.11 -n 255.255.255.0 -m 9000 VMkernel Hmm the output is …….. [root@esx sysconfig]#  esxcfg-vswitch -l Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch0       32          3           32                9000    vmnic0 PortGroup Name      VLAN ID  Used Ports  Uplinks VM Network          0        0           vmnic0 Service Console     0        1           vmnic0 Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks vSwitch1       64          3           64                9000    vmnic1 PortGroup Name      VLAN ID  Used Ports  Uplinks VMkernel            0        1           vmnic1 Property of vmknic [root@esx sysconfig]#  esxcfg-vmknic -l Interface  Port Group/DVPort   IP Family IP Address                              Netmask         Broadcast       MAC Address       MTU     TSO MSS   Enabled Type vmk0       VMkernel            IPv4      192.168.0.11                            255.255.255.0   192.168.0.255   00:XX:83:91:23:14 9000    65535     true    STATIC

Source: http://moizzy.blogspot.com/2010/02/configure-jumbo-frames-in-esx-4-for.html