Differences between Standard and Enterprise editions of Exchange 2007

Microsoft Exchange Server: Exchange Server 2007 Editions

One of the questions people often ask when figuring out what version of Exchange that they actually need is the limit on the size of the database. Microsoft has done a good job of putting together a quick and simple explanation of the differences on the page above which is really helpful for folks trying to plan and manage their Exchange environment. The cost of an Enterprise license is fairly more expensive than a standard edition, but you lose the flexibility and redundancy in your organization. For example, you cannot use CCR for clustering your Exchange environment and you are limited to just 5 storage groups with 5 different databases. The theoretical limit on exchange database size is 16tb which is the same for each version of Exchange but in reality the limit is much lower.

Microsoft has a support document that states the recommended maximum size for a database is 100gb due to the I/O involved with transaction logging and backup/restore functionality. You of course can go much higher but be prepared for some headaches along the way such as log file replaying and recovery time being a lot longer. It is a good practice to try to keep the databases around 100gb if at all possible. This is another advantage of the enterprise edition in that you can manage 50 different databases on a single server instance.

Always remember to keep your logs separated from your database on different logical volumes so that the I/O can be properly spread between the two sets of data. Most of this is common sense and very logical, but if you take these steps up front you will save a lot of headache down the road.