Friday, September 19, 2008

Setting up Jumbo Packets with ESX 3.5

First off, thanks to another blog

But there is one thing left out, i'll put it at the end.

Configuring ESX Server
There is no GUI in VirtualCenter for configuring jumbo frames; all of the configuration must be done from a command line on the ESX server itself. There are two basic steps:
Configure the MTU on the vSwitch.
Create a VMkernel interface with the correct MTU.
First, we need to set the MTU for the vSwitch. This is pretty easily accomplished using esxcfg-vswitch:
esxcfg-vswitch -m 9000 vSwitch1
A quick run of “esxcfg-vswitch -l” (that’s a lowercase L) will show the vSwitch’s MTU is now 9000; in addition, “esxcfg-nics -l” (again, a lowercase L) will show the MTU for the NICs linked to that vSwitch are now set to 9000 as well.
Second, we need to create a VMkernel interface. This step is a bit more complicated, because we need to have a port group in place already, and that port group needs to be on the vSwitch whose MTU we set previously:
esxcfg-vmknic -a -i -n -m 9000 IPStorage
This creates a port group called IPStorage on vSwitch1—the vSwitch whose MTU was previously set to 9000—and then creates a VMkernel port with an MTU of 9000 on that port group. Be sure to use an IP address that is appropriate for your network when creating the VMkernel interface.
To test that everything is working so far, use the vmkping command:
vmkping -s 9000
Clearly, you’ll want to substitute the IP address of your storage system in that command.
That’s it! From here you should be able to easily add an NFS datastore or connect to an iSCSI LUN using jumbo frames from the ESX server.

when doing the excfg-vmknic I got the following error:
"Error performing operation: A vmkernel nic for that portgroup already exists: PortGroupName"
I did a esxcfg-vmknic -d PortGroupName
Then you can follow the instructions as written.

========THE SHORT VERSION=========
The Setup...
esxcfg-vswitch -m 9000 vSwitch1
esxcfg-vmknic -d PORTGROUPNAME
esxcfg-vmknic -a -i -n -m 9000 PORTGROUPNAME (set your ESX IP on a portgroup)

To Make sure everything took......
esxcfg-vswitch -l
esxcfg-vmknic -l
vmkping -s 9000 (another host running jumbo frames)

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