Spec'ing an Exchange Server

What is the rule of thumb for maximum # of users and Exchange 2003 Ent (assume and active/passive cluster)?
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David WilhoitSenior Consultant, ExchangeCommented:
depends on many factors; user base, type of usage, your mailbox store limits and message size limits, type of Outlook client (O2003 allows a lot more users), and type of storage device (SAN, JBOD, internal, and type of RAID) Exchange depends on disk I/Os so spindle count is paramount to performance.

albertbrAuthor Commented:
Type of usage: heavy
Store limits: Unlimited (enterprise edition)
Message size limit: 50MB
OL Client: OL20 - OL03
Storage device: DAS/SAN (50K I/Os per sec)
David WilhoitSenior Consultant, ExchangeCommented:
Sounds like the Clarion CX300 or CX400. Check out the Optimizing storage doc from MS:


Depending on how many users you have at peak times, and how much I/O they generate, you'll need a lot of spindles, regardless of that big cache on the SAN. 50k I/Os a sec is the optimal cache performance, not the true flush-to-disk performance. The cache can get full if you have high traffic and not enough spindles to handle it all.


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