So after a long silent period apart from Outlook live lab videos on the Exchange blog, suddenly there is Exchange 2010 beta!

So what can you expect in the new industry standard mail platform, this is part 1.

Well the major change is in High Availability, take LCR, CCR and SCR from Exchange 2007, mix it all together and you have the best of all three! So there is no more LCR, CCR and SCR in Exchange 2010, but it is called Database Availability Group and so yes another acronym: DAG.

The major change is that Windows Failover Clustering is not involved in DAG, the high availability is at database level. You can have up to 16 (!) copies of each mailbox database spread over you mailbox server farm. There are no more storage groups, you now set the databases at organization level and not at server level.

Well that sounds really enterprise/datacenter level, well with just 2 servers you can have high availability! without the need of expensive cluster storage solutions. Copies of databases may be placed on servers that have other exchange servers installed.

Another major improvement that benefits DAG is the 50-70% performance gain in IOPS. So there is no need for expensive fast spindles for storage, you can use direct storage, even desktop class SATA disks. So with this cheap storage you can give your users larger mailboxes. Microsoft even claims you can use the cheaper SATA drives without RAID, since you have copies of the databases on other servers. So now you can have a performing high availability exchange solution at home :-)

But of course DAG works best in a datacenter environment, with 16 copies per database you can have site redundancy spread all over the world.

There has been no announcement yet about the Exchange SKUs, so I don’t know what form of DAG will be available in the standard edition, but LCR was available in Exchange 2007 in the standard edition which requires a manual recovery. I assume that 2010 standard edition will allow at least 1 database copy with automatic recovery support.

Another part of high availability is the new move-mailbox feature: online mailbox move. Now the end user can continue working with their email, reading, sending and receiving, while the administrator moves the mailbox to another server, all just during work hours. At the last stage the end user will expect a interruption, when the last sent and received email is copied over to the new location. So this is like Vmotion on VMware ESX (and soon Live Migration on Hyper-V

Functional Descriptions

Database Availability Group: A set of Mailbox servers that uses continuous replication to provide automatic recovery from a variety of failures (disk level, server level, datacenter level).

Database-Level Failover: Exchange Server Database Availability Groups provide automatic failover at the database level, without the complexity of traditional clustering. A database-level disruption, such as a disk failure, no longer affects all the users on a server. Because there is no longer a strong tie between databases and servers, it is easy to move between database copies as disks fail. This change, coupled with faster failover times (30 seconds), dramatically improves an organization’s overall uptime.

Improved Site Resiliency: Exchange Server Database Availability Groups makes it easier to implement site resilience by simplifying the process to extend data replication between datacenters to achieve site failover. Log files are also compressed to improve transmission time and reduce network bandwidth usage.

Easier Deployment: Administrators can add high availability to their Exchange environment after their initial deployment, without reinstalling servers. Small organizations can deploy a simple two-server configuration that provides full redundancy of mailbox data along with Client Access and Hub Transport roles. These changes put high availability within the reach of organizations that once considered it impractical.

Integrated Cluster Administration: Exchange Server Database Availability Groups feature automatic failover without the complexity of traditional clustering. The proven capabilities of Windows clustering are integrated with Exchange and are transparent to the administrator. Administrators no longer need to master clustering concepts or deal with separate administration tools in order to provide enterprise-class uptime.

Backup-less Support: The Exchange Server Database Availability Group architecture allows log file replay to be lagged, enabling administrators to perform point-in-time database restores without the need for tapes. Organizations can rely on their high availability infrastructure rather than tape backups to recover from failures, and substantially decrease their operating costs.

Transport Resiliency: Transport servers in Exchange Server 2010 feature built-in protection against the loss of message queues due to disk or server failure. Servers retain a "shadow" copy of each mail item after it is delivered to the next hop inside the organization. If the subsequent hop fails before reporting successful delivery, the message is resubmitted through a different route.

Check back Monday for part 2

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