vSphere Hypervisor

Hi Guys,

I've inherited a VM system at my new job and looking over the configuration which I feel is incorrect but would like a steer from some on you experts.

The System

1 Dell Compellant FC Storage

3    VM Hosts

The hosts have the following NIC assigmnets

2 x 10GB cards configured a a pair, servicing all Virtual Machine VLANs

2 x 1GB cards for Management (VMKernal Port)

4 x 1GB cards for VMotion

All the 1GB cards are using an MTU of 1500

One of the Hosts is using MTU of 9000 for the 10GB cards but the other 2 are using an MTU of 1500

The switches are using an MTU of 1500 for all VLAN - HP 2920 switches, they seem to assign Jumbo Frames on the VLAN no the switch ports

Should I enable an MTU of 9000 for the VMotion cards - and switch VLAN for VMotion - and also the 10GB cards and the switch VLANs that these cards carry?

Do you have any suggestions for a better configuration?

Also, these hosts are providing a live environment. How would you suggest any changes are made to prevent an outage - if this is possible?

Any help would be really appreciated

In simple terms, if we enable jumbo frames it should be from end to end(vswitch, all physical switch ports, destination host or vswitch level), else there wont be any use of it. In your case, you say that jumbo frame is enabled at host level but no at physical switch which is of no use.

The below links should help..

Enabling Jumbo Frames on virtual distributed switches (1038827) | VMware KB

Networking Best Practices for vSphere vMotion

Thanks for your replies guys.

Do I actually need Jumbo frames enabled if I use a FC SAN?

I can understand the need for Jumbo Frames when if I was using iSCSI but not so sure with FC. Any thoughts?

Jumbo frames are only for IP network, since iSCSI uses IP network you may use it.

FC (fiber channel) uses different protocol which doesnt has jumboframes concept.

Thanks guys.

Your input was very helpful.