There is a LOT to like with Exchange 2010 but what really stands out for me is the the way HA has been revamped. Microsoft is building on the success of continuous replication found in Exchange 2007 with new Database Availability Groups while dropping SCC and LCR from the lineup.
Exchange 2010 builds on the continuous replication technology used for CCR and SCR in Exchange 07 and combines them into a single type of clustering called Database Availability Groups, or DAG. The DAG provides automatic failover for both on-site and off-site data replication. The keyword here is automatic.
In Exchange 2007 off site data replication was handled with SCR and required significant manual intervention to failover and then more to failback. While SCR was a nice addition to Exchange for BCDR scenarios it was still limited. DAG provides failover automation similar to that found CCR environments but with the ability to replicate up to 16 instances.
DAG relies on much of the same underlying technology found in CCR style clustering which includes log shipping and database replay on top of a Node and File Share Majority quorum platform. Microsoft has always recommended that the File Share Witness (FSW) reside on the Hub server in Exchange 2007 and this recommendation continues in Ex2010.
Cluster setup has been simplified and only relies on the heartbeat and database capabilities of the underlying cluster subsystem.
Another bonus to administrators is the ability to combine multiple server roles on HA mailbox servers to provide redundancy for CAS and HUB servers. This may be a useful configuration when trying to achieve higher server consolidation ratios in some shops while other designs may still call for separate roles based on performance or security reasons.
Another welcome change is the functionality to use a single, admin defined TCP port for log shipping AND the ability to encrypt and compress that replication stream during transfer!
"Log shipping and seeding no longer uses Server Message Block (SMB) for data transfer. Exchange 2010 continuous replication uses a single administrator-defined TCP port for data transfer. In addition, Exchange 2010 includes built-in options for network encryption and compression for the data stream."
More info here:
http://technet.microsoft.com/en-us/library/dd633496(EXCHG.140).aspx
Part 2 will look at sample HA designs based on DAG ..
Im posting the original PowerPoint 2007 file that was used for the VMware Port graphic in case anybody wants to use it. Feel free to fix it up or modify for your own use.
There is also a port requirements document being worked on through the VIOPS site at VMware. Click here for the document
Vmware released some great new icons a few week ago through the VIOPS site and I had to do something with them. The pic below comes from a larger PowerPoint presentation I was working on recently that show the port requirements for a typical VI3 deployment.
