The solution presented in this document is designed to simulate a large number of mailboxes hosted on highly redundant hardware. Application level redundancy is augmented with redundant storage to create a highly available and fault tolerant solution.
The Mailbox Resiliency features of Exchange 2010 have greatly enhanced the availability of Exchange 2010, while also improving I/O performance. The solution presented here is a Mailbox Resiliency solution utilizing 1 Database Availability Group (DAG) and 2 copies of every database. The tested environment simulates all users in this DAG running on a single Storage Center or half of the solution. The number of users simulated was 10,000 across 4 servers, with 2,500 users per server. The mailbox size was 2GB per user. Each server has 4 databases, with one copy local and the second copy replicated to the second server. This provides redundancy through hardware and software.
The replication mechanism is the native Exchange 2010 DAG log shipping engine. This is a very efficient and reliable replication mechanism and is the recommended method for providing highly-available and redundant Exchange solutions.