Exchange 2007 High Availability Sessions

Thursday, June 7, 2007
Today was an "all Exchange, all the time" day. The sessions I attended dealt with Exchange 2007 high availability and disaster recovery.

One was presented by Ayla Kol entitled, "High Availability in Microsoft Exchange Server 2007 and Exchange Server 2007 Service Pack 1". She did a good job explaining what's offered in E2K7 RTM for HA and went on to explain what's going to be new in SP1. Here are the highlights for RTM:
  • Windows 2003 needs KB921181 to enable File Share Witness (FSW)
  • Continuous Cluster Replication (CCR) is limited to 2 nodes
  • CCR requires hardware from the Geographically Dispersed Cluster category of the HCL
  • FSW should be on hub in primary site
  • CCR nodes must be in the same subnet. This poses a problem for geo-clustering
  • Best Practice to use a CNAME record for the FSW name. This provides easier failover
  • Best Practice to increase tolerance of heartbeat failures to 10
  • Log shipping to the passive node is a pull model. The Replication Service monitors logs
  • Divergence = loss of mailbox data. This is what happens in a "lossy" recovery. Normally, in CCR the hub's transport dumpster will backfill the recovered node with missing data.
  • LLR = lost log resilience. This is what the transport dumpster is for.
  • The transport dumpster works only with CCR in RTM. It will work with LCR in SP1
  • Recovery from transport dumpster is designed to backfill within 30 seconds
  • SP1 will have a GUI for cluster management (finally!)

And now for what we've all been waiting for, Single Copy Replication (SCR)!

  • SCR will be included in SP1
  • Possible scenarios include: Standalone server to SCR, LCR to SCR, and CCR cluster to SCR
  • Designed for datacenters
  • CCR can use dissimilar hardware. This offers simplified hardware and storage requirements. Does not require hardware from the Geographically Dispersed Cluster category of the HCL
  • No subnet requirements! Can work across different subnets, unlike CCR
  • Only works with one database per storage group
  • Must be same paths

In a future blog, I hope to write more about CCR and SCR. For now, we're off to the TechEd attendee party at Islands of Adventure. The kids are gonna have a blast!