NLB Unicast Mode over two different ESX hosts?

[jslarouche]

Hey guys,

Is anyone out there have NLB setup as unicast and have them spilt

across multiple ESX hosts? If yes, how is it configured? I’ve got two VM's setup on

each ESX hosts I have the vswitch port group to have the set to notify switch to

"NO". I have each two NICS to both VM's binded to that port group. Everything seems to work but sporadically when we are on

the console of one of the VM's or on the other VM each has trouble pinging other servers on our

network. It's kind of weird. It comes and goes. It's like the communication of the OS of the VM wants to go down the NLB NIC and stops communicating.The two VM's have each two NICS and are all IP'ed

in the same subnets. I am using a host file so that the NLB Manager can resolve the hostnames

properly when you load the mmc and both servers comes up green in the NLB Manager. Just having

strange communication problems. So if someone can help me out with the proper

config that would be great. I undestand that multicast is the way to go but our networking team is not allowing us to use that feature internally so unicast it is..

[AndreTheGiant]

Have a look at this KB:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1556

If you plan to use NLB unicast mode, you must run all members of the NLB cluster on the same virtual switch or routers need to be able to accept proxy ARP responses (IP-to-network address mappings that are received with a different network source address in the Ethernet frame).

See also:

http://kb.vmware.com/kb/1006580

Andre

[jslarouche]

So theres no way of having these split up on two different hosts?

[azn2kew]

We have bunch of Sharepoint 2007 and IIS 7.0 web servers running with NLB mode and using same instructions listed here and it all depends what you use that you have to configure your virtual switch differently for unicast/multicast.

If you found this information useful, please consider awarding points for "Correct" or "Helpful". Thanks!!!

Regards,

Stefan Nguyen

VMware vExpert 2009

iGeek Systems Inc.

VMware, Citrix, Microsoft Consultant

[jslarouche]

Great thats good to know.. Are they split onto two different hosts?

[jslarouche]

Well the issue is that the WIndows NIC bindings settings under the Advanced options was set to NLB first so all we had to do is is flip the NICS.. We now have two VM's on two different hosts running UNICAST.. So it is do-able for anyone who cares.