Saturday, June 19, 2010

ESXi - Enabling SSH and Jumbo frames.

Enabling Jumbo frames on the ESXi server took me some time as most people suggest me to enable SSH and the login to the unsupported console and enable the jumbo frames. This is not supported by vmware. If you have a evaluation version running on a test machine you can try this.
We decided to go with ESXi installation on our Sun servers and HP servers and we enabled Jumbo frames on the switches and the Netapp storages. We enable on the real production machine through vSphere CLI.  I will write about that in next session.

1) Enable SSH on the ESXi hosts
  a) Go to the console of the ESXi host and press ALt+F1
  b) Type "unsupported" on the window, this text wont be echoed.
  c) Enter the root password, you will get the prompt ~ #
  d) Edit the file /etc/inetd.conf
         ~ # vi /etc/inetd.conf
  e) Remove the # from the line ssh.
   ssh     stream  tcp     nowait  root    /sbin/dropbearmulti     dropbear  ++min=0,swap,group=shell -i -K60

  f) Determine the process id of inetd from the command
           ~ # ps | grep inetd
  g) Restart the inetd
           ~ # kill -HUP

2) Enabling Jumbo frames

  a) Login to the server using SSH
  b) esxcfg-vswitch -l  , This will lists the current vswitches including the MTU sizes

~ # esxcfg-vswitch -l

Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0       64          3           64                1500    vmnic2

  PortGroup Name      VLAN ID  Used Ports  Uplinks
  VM Network          0        0           vmnic2
  Management Network  0        1           vmnic2

  c) Set the Jumbo frames for the vswitch0

     ~# esxcfg-vswitch -m 9000 vSwitch0

  d) Check the changes
  
~ # esxcfg-vswitch -l
 
Switch Name    Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0       64          3           64                9000    vmnic2

  PortGroup Name      VLAN ID  Used Ports  Uplinks
  VM Network          0        0           vmnic2
  Management Network  0        1           vmnic2



  e) Verify that that the NIC has the new value

     ~ # esxcfg-nics -l

      vmnic2  41:00.00 bnx2        Up   1000Mbps  Full   18:a9:05:68:cd:d0 9000

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