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Using multiple mailbox stores effectively

Here are a couple of examples of how to take advantage of multiple mailbox stores.

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Exchange Server 2003 Enterprise Edition has a maximum store size of 16 terabytes. I don't know anyone whose mailbox store is even close to this size, and yet Exchange allows you to create up to 19 additional stores, for a maximum storage capacity of 320 terabytes. (Technically, Exchange would even allow databases to grow beyond this size, but the NTFS file system imposes a 16 terabyte limit).

As if that isn't enough, you can have multiple servers in your Exchange organization, providing you with a virtually unlimited amount of possible storage space.

This all adds up to way more potential storage than anyone could ever conceivably use (and current hardware limitations prevent a server from ever actually reaching the limit anyway).

So if you take the need for increased storage space out of the equation, what are the advantages of having multiple mailbox stores?

1. You can set mailbox quotas at the mailbox store level.

For example, suppose that one of your Exchange servers was beginning to run a little low on hard disk space. To help manage disk space consumption, you set a 50 MB limit on the size of each mailbox. However, upper management does not want that quota to apply to them.

In this type of situation, you could move the managers' mailboxes into a separate mailbox store. You could then implement a 50 MB limit on the store containing most of your users' mailboxes, but set no limit on the store containing the mailboxes for upper management.

2. You can place users into specific message stores based on their e-mail behavior patterns.

For employees who heavily use Exchange for legitimate business and have to frequently refer back to old messages, Exchange includes a full-text index feature that allows them to search old messages in a much more efficient manner -- because they are searching against an index rather than against the actual database.

The downside to full text indexing is that the process of creating and maintaining the indices tends to be very resource-intensive for Exchange.

If, however, you can distinguish those who use e-mail for business purposes from those who use it for more frivolous reasons, you can create a separate mailbox store for the heavy users. You could then enable full text indexing only for their store -- where it is really needed. This helps conserve system resources.

These are just a couple examples of the many different ways you can better manage your data and system resources with multiple mailbox stores. Most settings that can be applied at the store level can be used to benefit your system in some way ... with a little imagination.

About the author: Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer he has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal Web site at

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