Hello, I am looking at the pro and cons Exchange Mailbox server clustering. "Configure the failover cluster quorum, that is, create the file share on a separate server (best practice is to use a Hub Transport server in the same AD site as the failover cluster nodes" So without clustering i have my one Mailbox server. If it fails all those mailboxes go down. Withclustering i have my one Mailbox server, and one hot spare. If it fails all those mailboxes stay up because the second host in cluster will pick up the load because the quorum is stored on my Seperate Hub Transport server following Best practise. But then what happens if my HT server fails? I still loose my mailboxes. So it hasnt really reduced downtime possiblity in anyway only added to admin overheads and costs. The singlehardware failure possiblity has just moved from MB server to HT server. It will still only take 1 server to fail as in the first non clustered scenario, just a different one. Am i correct or have i missed something? So the only way for this to really work in a HA suituation is to have the quorum stored in a mirrored SAN environment$$$ Thanks

Hi, An update is available that adds a file share witness feature and a configurable cluster heartbeats feature to Windows Server 2003 Service Pack 1-based server clusters Here is the information about MNS/quorum on CCR cluster. MNS/Quorum just acts as a referee when heartbeat communication fails between both nodes in CCR, passive node thinks that active went down and I need to take charge then referee says I can still communicate the current active node and you stay there and dont become active and in this way split brain condition doesnt happen.You are professionH So I think when Hub Server (MNS/Quorum/referee) goes down it really doesnt affect your mailbox productivity until heartbeat communication between both nodes is normal.

Thanks for that link, that is a lot of information to take in. But just so i know i have read what i need to do correctly. Where does my Mail Store live, when i have 2 Mailbox servers in a cluster? I thought that it was on the HT server, and the 2 MB servers were pointing to it. but it appears what you are saying is that the Quorum just acts as a referee. so the Quorum is the thing that decides if one of the machines has really gone down. Is if that was the case then were is the mailstore? Is there a copy on each MB server? Are they replicated across the heartbeat nics, or does it have to go through the other nics. Can the Heartbeat nics just use a cross over cable?

The mailbox databases would exist on the mailbox servers as in a CCR cluster there is an active and passive CCR node, each with complete copies of the databases. http://www.msexchange.org/tutorials/Installing-Configuring-Testing-Exchange-2007-Cluster-Continuous-Replication-Based-Mailbox-Server-Part3.html

thank you this was the tutorial i was following, i got a bit lost on Part2 with the Quorum and now i can move ahead, knowing exactly what i am doing and what i have to do to get it to work. Can the Heartbeat nics just use a cross over cable? so what happens if the HT with the Quorum fails? Does that mean that the MB servers are only relying on their heartbeat? or will it mean that when the HT is not on the MB can not swap over to the hot MB server?

To verify that all network connections are correct, private network adapters must be on a network that is on a different logical network from the public adapters. This can be accomplished by using a cross-over cable in a two-node configuration or a dedicated hub (not a smart hub) in a configuration of more than two nodes. Do not use a switch, smart hub, or any other routing device for the heartbeat network. - Cluster Installation Refer these articles for optimal setting of heartbeat network settings & also CCR network configuration. Recommended private "Heartbeat" configuration on a cluster server Cluster Continuous Replication When HT server is not available, where quorum is sitting, you will get errors on both of the nodes andpossibilities of split brainare high in case heartbeat network fails otherwise it can failover to passive node if active goes down butDR tests with some of the test mailboxes are always better before putting servers into production to get exact idea what happens, when and which kind of errors we get so during problem you can quickly identify & give solution.

Speaking of heartbeats, failover, and CCR Log shipping... I am setting up a cluster and was wondering which NIC's to use for the Log shipping? If I use the Public NIC's I am competing with users accessing email - if I use the Private NIC I am competing with cluster traffic (and the ExBPA complains that the setup is not "best practice" to configure the Private NIC in Mixed Mode) and you could have cluster problems. So where do I configure CCR? Public, Private - or should I add a third NIC to each node and use that?