General questation about NLB

[MarekGr]

Hi ,

sorry for my bad Englisch . I have basic questation about NLB in the Vmware . I have two virtual machines with created unicast NLB . I set notification switches off .

Now I have trouble with connect to this cluster nodes . If I in the same host and same distributed switch I cannot connect to the another cluster node which run on another host 

thanx for help

[Josh26]

It's a recurring question here.

The short of it is that the caveats on Unicast NLB make it unworkable. You will find Multicast NLB pretty much works "out of the box" if you setup your router with the traditional ARP entries that are required in a physical environment.

[MarekGr]

any solution how I set unicast to work ? NLB work ok , only this not work ...

[Josh26]

Since you didn't want to follow my advice above, I will post VMware's official statement on Unicast NLB. YOu will note the first bullet point precludes you from running it on two nodes.

VMware recommends configuring the cluster to use NLB multicast mode even though NLB unicast mode should function correctly if you complete these steps. This recommendation is based on the possibility that the settings described in these steps might affect vMotion operations on virtual machines. Also, unicast mode forces the physical switches on the LAN to broadcast all NLB cluster traffic to every machine on the LAN. For more information on the differences between multicast and unicast, see Microsoft Network Load Balancing Multicast and Unicast operation modes (1006580). If you plan to use NLB unicast mode, note that:

• All members of the NLB cluster must be running on the same ESXi/ESX host.
• All members of the NLB cluster must be connected to the single portgroup on the virtual switch.
• vMotion for unicast NLB virtual machines is not supported (unless you want to migrate all NLB members to a different ESXi/ESX host).

[MarekGr]

thank you

I read our advice , but NLB unicast  in our organization install support organization and I want idea from another people .

[Josh26 · Accepted solution]

If you have an IT support agent encouraging Unicast NLB in this scenario - let them try and fix it.

I would hope that they would either realise the error of their ways - or be replaced.

[MarekGr]

and last questation about this.

multicast from M$ or standart IGMP Multicast ?

[Josh26]

My discussion has been a reference to using Multicast NLB over Unicast NLB. These are the two deployment scenarios for Microsoft NLB.

[MarekGr]

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100655...

i look to this kb , there is in the picture selected M$ Multicast but in another site is this type of multicast write nostandart multicast

[Josh26]

I'm trying to understand your concern.

Are you suggesting you won't use Multicast NLB because you read somewhere Microsoft use something non-standard?

I can't tell you if this is true - but I can tell you that there is nothing more "nonstandard" than the way Unicast NLB is supposed to work - which is why it doesn't.

[MarekGr]

no no no ... unicast I do not want !!!!

i look to difference bettwen mutlicast and multicast IGMP . I try in the the test vmware set the multicast . I create multicast NLB and this NLB is configured . But without setting cisco switches i cannot connect to this from other sites . this is ok . But if I configure with Multicast IGMP the NLB I cannot assembled ...