Two Server Exchange 2010 DAG with High Availability (Full Version)

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sockitsolutions -> Two Server Exchange 2010 DAG with High Availability (28.Mar.2010 6:39:20 PM)

I have a quick question re: Exchange 2010, DAGs & High Availability. I've set up two Exchange 2010 servers and set up a DAG that includes them both. According to Microsoft, I need to set up a hardware load balancer in front of those two servers in order to provide high availability.

My question is, why can't I use the static IP address I've assigned to the DAG instead of a load balancer? The failover IP address is assigned to one of the servers, and in the event that server goes down, the second Exchange server takes over that IP address and my mail services are still available. Is there something I'm missing?


neilho -> RE: Two Server Exchange 2010 DAG with High Availability (29.Mar.2010 12:09:40 PM)

The DAG IP address has nothing to do with the RPC Client Access service running on your CAS role, which is the service that Outlook clients connect to.

You will need to load-balance the CAS role to achieve high availability and as you've probably read you can't do this with Windows NLB on the same servers running a Windows Failover Cluster. You will need a hardware load balancer.

sockitsolutions -> RE: Two Server Exchange 2010 DAG with High Availability (1.Apr.2010 10:44:18 AM)

Thanks for the quick reply.

It appears as though the DAG IP address is set up as an IP Address Resource in the Failover Cluster Manager. As a result, that IP address is always either assigned to EXCH1 (my first Exchange box) or EXCH2.

As a test, I created a DNS record to point to the IP address set up by DAG, set up the CAS array and assigned that array to my mailbox. Using that new DNS hostname, clients are able to access all services (OWA, Outlook Anywhere, SMTP, etc.) and in the event I disconnect EXCH1, EXCH2 takes over and clients can still access all services. Since I'm just looking for EXCH2 to take over when EXCH1 fails, it seems like a solid setup. I imagine this is how the IP Address Resource was designed to be used in Failover Clustering, so even though it was set up by DAG I don't see why it cannot also be used as the address in which clients access mail services.

bobbysworld1 -> RE: Two Server Exchange 2010 DAG with High Availability (9.Apr.2010 12:17:07 PM)

I am also interested in failing over one Exchange 2010 server to another using DAG. Both servers have CAS/HT/MB. I do not have load balancing setup, so i would like to use the DNS resolution you described here. Would someone be able to break it down a little bit and explain the steps to setting up the fail over so that DNS can point Outlook clients to  Exchange Server B when Server A is no longer responding?

Thanks in advance.

WrathyImp -> RE: Two Server Exchange 2010 DAG with High Availability (30.Sep.2010 4:18:15 AM)

Hi bobby,

were you able to resolve your setup using DNS round robining, As its long time now, i hope you have alreday over come the failover for CAS.
Could you mention this here, as i am also on the same setup of having two excahnge 2010 with MB/CAS/HB and DAG.

Awaiting your response that will help be set my upgrade plans.

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