[c-nsp] VMware teaming Nic's and multiple switches

[Jeff Kell]

We did cross-chassis port channels on 3750s for years.  However, the new
vCenter/ESX 5+ has this automatic link balancing thing.  You setup the
trunks all the same, no need for port-channels, and the vCenter host
load-balances the vlans/hosts across the available links.

Kinda ugly from the switch side, and unpredictable, but seems to work. 
Would love to hear from someone with more experience doing this.  We had
a request from our systems group to do this on their new vCenter cluster
and we've accomodated them, somewhat reluctantly, but so far no issues.

Jeff

On 9/19/2012 6:13 PM, Peter Rathlev wrote:
> On Wed, 2012-09-19 at 14:48 -0700, Scott Voll wrote:
>> If I have a VM physical server I can team two nics and then do a port
>> channel on the switch.
>>
>> Can this be done if I have two switches?
> That would require switches capable of cooperating more than usual.
> Matts suggestions of 3750 Stackwise and Nexus vPCs cover the bases.
>
> You might not need MLAGs though. We run many stand-alone trunks from
> 3750 and 3560 switches to VMware ESX hosts and let the vSwitch on the
> host spread out the guests between these links and take care of
> failover. It works really well and does not require any proprietary
> protocol to work.
>
> Using this method means that no single guest can consume more that one
> link, but deterministic hashing a la what Catalyst switches do has the
> same limitation.
>