Cluster Continuous Replication between 2 datacenters
Here's the scenario: 2 data centers on 2 different subnets. Currently we have exchange 2003 installed on a single server. My boss wants a high-availability implementation with automatic failover. (Zero admin intervention in the case of a failure.) I saw the CCR replication and it talked about the capability to do it between datacenters, but it appears that they need to be on the same subnet. Has anyone implemented a High Avail configuration between datacenters? Am I barking up the right tree? Presently each datacenter has its own site in AD. (Hated to state the obvious, just wanted to be sure.) If this isn't possible, out of the box, does anyone know of a 3rd party solution? Thanks!!!
October 2nd, 2008 5:26pm

This is indeed the correct tree! This is very possible, and I am among many people who set it up often. Exchange 2007 can reside on Windows 2003 or Windows 2008. Windows Server 2003 does not support clustering across different subnets. For Windows 2003 you need to create a "Stretched VLAN" that will allow the same (possibly new) subnet to live in both locations. Windows Server 2008 supports multi-subnet clusters. Do yourself a favor and take an hour out of your day to watch this webcast. It was really good, and It helped me significantly when I had to design my first "geo-cluster". http://msevents.microsoft.com/CUI/WebCastEventDetails.aspx?culture=en-US&EventID=1032364834&CountryCode=US Additional resources: http://www.microsoft.com/windowsserver2008/en/us/clustering-multisite.aspx http://support.microsoft.com/kb/947048/en-us Finally, there are several 3rd party solutions in this space. www.steeleye.com www.doubletake.com www.neverfail.com
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October 3rd, 2008 6:49am

Brain,Yes it is possible to build a geographically dispersed CCR cluster. As Mike indicated below, the link for the webcast is quite helpful. The only minor issue you may come across is the DNS update times for the cluster related entries. As far as the third party cluster solution goes, nothing comes close to NeverFail solution. I have worked with them (and the others) and the results were excellent. In fact we built a NeferFail cluster solution at the DR site to protect a headquarters Exchange CCR cluster. Other vendors (Doubletake being most known) didn't (probably still don't) have a Cluster protection solution yet.CheersCem
November 29th, 2008 11:49am

Yuo should also have things such as the following in mind: The nodes in a Geo-CCR must be located in the same AD site. This means that clients as well as inbound/outbound e-mail messages can choose to connect to a Client Access/Hub Transport server in the opposite physical site. This can put a significant unexpected burden on the connection between the sites. As was mentioned already DNS cache may play games with you, even though you lower the TTL. Remember that the FSW must be online if/when one of the nodes goes down. This means some organizations places the FSW in a third site. Alternatively you can just recreate it, but this means you'll have manuel steps to perform during a disaster where the site hosting a node and the FSW is down. You may also choose to pause the Windows cluster as you probably don't want automatic unplanned failover to occur between the sites. Also consider the transport dumpster on the Hub Transport servers. What I'm really trying to say is that CCR clusters never were designed for Geo-clustering purposes, this is why SCR was introduced in E2K7 SP1.
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November 29th, 2008 10:15pm

Also, there's CCR webcasts onMicrosoft Exchange Server 2007 in Depth.
February 17th, 2009 2:22am

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