In my previous blog entry I overviewed the failover procedure for Rockerduck and what ‘technically’ goes on in the background during a failover. This blog entry will focus more on the client experience during and after an outage.

Imagine that Jim and Kelly are both a part of “ABC Company LLC”. Jim is very hip with his new Apple laptop using Office 2011 and his iPhone 4s. Kelly still uses Windows along with Outlook 2007 and when she is out of the office she uses her Blackberry Torch connected through Blackberry Enterprise Server.

Currently, everything is working properly and all systems are operational.

If MBOX2 was to go offline, MBOX1 would take over actively hosting DB2 (Which was hosted by MBOX2). This type of failure is an inter-site failure and results in an immediate switch to the passive copies. Customers will see no downtime as long as there is a good copy of the database available.


What happens if Dallas goes offline?


As described in my previous blog entry, disastrous failures are not automatically failed over. At this point, both clients would be offline from their mailbox and unable to access, create or modify items.

However, in following my previous blog entry we would be able to activate our fail over procedure.

After 15 minutes of electing to activate our fail over procedure clients should receive the update DNS records for to point to Los Angeles. All clients would then be able to reconnect to their mailboxes and service should resume as normal out of Los Angeles with the exception of Blackberry Enterprise Server which cannot be setup for fault tolerance in our network design.

After repairing/resolving any issues in Dallas, we would then begin to resynchronize the databases from Los Angeles to Dallas. Once all database copies are up to date we would then reconfigure DNS to point to Dallas and resume service as normal. All in all with a disastrous failure we would be able to recover from the event in 15 minutes once the recovery process is executed.

Travis Sheldon
VP, Network Operations, ExchangeDefender
(877) 546-0316 x757