Load Balancers or NLB? (Full Version)

All Forums >> [Microsoft Exchange 2010] >> High Availability


Pantherfan -> Load Balancers or NLB? (17.Feb.2010 4:15:07 PM)

I am wondering if anyone here has exchange 2010 in production in HA setup, and if so are you using NLB service on your CAS servers, a hardware load balancer in front of them, or doing some kind of proxy in front of them?

I would like to have my cas servers be internet enabled, as well as used by local clients and be highly available.

Also, if I understand right, activesync clients remember which cas server they go through, and dont "fail over" if there is an issue?

josiahkuenzi -> RE: Load Balancers or NLB? (23.Feb.2010 11:41:17 AM)

Does anyone have opinions of this Exchange 2010 model which includes NLB on same severs having DAG?

For tight budgets, implement HA with just 2 Exchange servers (not implementing Edge since they have another messaging hygeine product already in place). Install HB, MB, and CAS roles on each server, the provide an external load balancer.

IF this can be Microsoft NLB provided by a third machine as stated below, what do you think of configuring one of the Domain Controllers with NLB to provide NLB for the CAS role? This would save on licensing costs (at least $2999 for Windows Server 2008 R2 Datacenter edition)

I am not really sure how one would get away with running WLBS on just the DC. Every time I have configured NLB -- You must have multiple nodes in a cluster. -- How would this be configured to provide NLB to CAS roles without making the Exchange servers part of an NLB cluster? WNLB and clustering which is being used by the DAG on the MB role have some sharing conflicts and should not be combined.

HI we have this scenario implemented on a custmoer site: A redundant server was configured as a network load balancer for 2 exchange 2010 servers. I would recommend that you install the CAs rol on both exchange 2010 server and the mailbox server as well. EG server 1 can be exc01, server 2 can be exc02. Set the NLB as exchange. Get all your clients to point at exchange. for DAG you can use the nlb machine as the witness disk. This scenario works brilliant. In short configure nlb on a redundant server or even a vm if possible and you will be up and running.

With Exchange 2010 you ca build redundancy with just two servers.
Install the HUB/CAS/MBX server role on each server. And provide an external loadbalancer, which can be Microsoft NLB provided by a third machine, which you can use as a FSW.
The question I have is: Is it possible to setup Windows NLB on a DC or a 3rd Windows 2008 R2 server and make the load balancing work for the CAS role?
jjdurrant:Yes, but it requires clustering


I have setup NLB for CAS 2007 exactly as Henrik Walther's article describes, however I have never seen NLB configured on a separate server. Usually NLB is configured on both CAS nservers, but I don't think that is possible when CAS 2010 is also with MB role since MB with a DAG uses other clustering features that would interfere.

Has anyone ever setup NLB on a separate 3rd server to provide load balancing for the CAS role? If so how do you do it?

Page: [1]