I'm making a new Exchange 2010 design for a company with 400 users. We have two datacenters with a fast fiber connection (1 gbit/s) between the datacenters. Both datacenters have a fast internet connection. Users are only located in one datacenter. The other datacenter is for fallback purposes only. There are no Active Directory site definitions created. We would like to have HA for Exchange 2010 but the budget is limited. So that's why we are considering to implement a stretched VLAN connecting both datacenters and using the following Exhchange infrastructure: Datacenter1 (active datacenter): 1 server with Hub Transport / Client Access Server roles 1 server with Mailbox Role with DAG (containing active mailbox copies) 1 TMG 2010 with Edge role Datacenter2 (passive datacenter): 1 server with Hub Transport / Client Access Server roles 1 server with Mailbox Role with DAG (containing passive mailbox copies) 1 TMG 2010 with Edge role I'm considering to implement a single CAS array containing the CAS servers in both datacenters and also to use Windows NLB for the CAS and Hub Transport roles. Also inbound SMTP (coming from the internet) will be spread across both datacenters by using MX preference records. Since there is a fast and reliable connection between the two locations I guess this should work just fine. Any comments on this?

I'm making a new Exchange 2010 design for a company with 400 users. We have two datacenters with a fast fiber connection (1 gbit/s) between the datacenters. Both datacenters have a fast internet connection. Users are only located in one datacenter. The other datacenter is for fallback purposes only. There are no Active Directory site definitions created. We would like to have HA for Exchange 2010 but the budget is limited. So that's why we are considering to implement a stretched VLAN connecting both datacenters and using the following Exhchange infrastructure: Datacenter1 (active datacenter): 1 server with Hub Transport / Client Access Server roles 1 server with Mailbox Role with DAG (containing active mailbox copies) 1 TMG 2010 with Edge role Datacenter2 (passive datacenter): 1 server with Hub Transport / Client Access Server roles 1 server with Mailbox Role with DAG (containing passive mailbox copies) 1 TMG 2010 with Edge role I'm considering to implement a single CAS array containing the CAS servers in both datacenters and also to use Windows NLB for the CAS and Hub Transport roles. Also inbound SMTP (coming from the internet) will be spread across both datacenters by using MX preference records. Since there is a fast and reliable connection between the two locations I guess this should work just fine. Any comments on this? Windows (software) NLB is not supported anymore by Microsoft. Rest looks good.. Gulab | MCTS-MCITP Messaging: 2010 | MCTS-MCITP Messaging: 2007 | MCC 2011 | Skype: Gulab.Mallah

Thanks for your reply. About Windows NLB no longer being supported. Do you have a reference supporting that statement? I know Microsoft does not recommend it in enterprise deployments of Exchange 2010, but only 400 users in one active datacenter can hardly be considered as an enterprise deployment, right? I did find recommendations regarding to Windows NLB but no statement Windows NLB is no longer supported. http://www.stevieg.org/2010/11/exchange-team-no-longer-recommend-windows-nlb-for-client-access-server-load-balancing/

It looks good. WNLB IS supported for the Hub/CAS servers. It is not supported for Mailbox servers but you are not trying to do that so I dont understand Gulab comments

It looks good. WNLB IS supported for the Hub/CAS servers. It is not supported for Mailbox servers but you are not trying to do that so I dont understand Gulab comments Thats what i meant, i missed that Mailbox Server Part... My Bad ;)Gulab | MCTS-MCITP Messaging: 2010 | MCTS-MCITP Messaging: 2007 | MCC 2011 | Skype: Gulab.Mallah

Thanks!