HP StorageWorks 8000 Enterprise Virtual Array and Microsoft® Exchange Server 2003

In order to fully comprehend the design decisions made in regards to configuring the EVA subsystem, an understanding of the Exchange Server 2003 workload characteristics is important. Exchange Server 2003 is a two-phase commit, transactional workload. Exchange data is first written to a log file and then committed to the database. This leaves two main workloads to characterize, database and transactional logging. Exchange Server 2003 contains two database file types, edb and stm. Data is stored in edb files when accessed by MAPI clients and will be the focus of this white paper. An Exchange stm database is utilized by Internet protocol clients such as OWA, POP3 and IMAP.

In normal operations, transactional logging is a 100% sequential write activity with an average data block transfer size of 4-8Kb. For Exchange database activity, the workload is a mixture of reads and writes. Generally, the breakdown is between 60/40 and 75/25 read/write ratio, and is heavily randomized. The data block sizes for reads and writes are small, in the 4-16Kb range. Exchange database write activity will also exhibit a bursty behavior, resulting in small periods of low activity followed by a burst of hundreds to thousands of I/O operations per second against the storage subsystem.