Plan Public Folder Limits in Exchange 2000

If you plan to use the public folders regularly, Microsoft recommends that you consider the maximum size of these folders, and then implement the limits before you make the folders available to users. This order is important for a number of reasons:

•	Messaging Application Programming Interface (MAPI) clients such as Microsoft Outlook can only use the default public folder tree, which is associated with the default public folder store in the first storage group that is created on each Exchange 2000 computer. If you want all of your public folders to be accessible over MAPI, you need to limit yourself to one public folder store for each server.
•	Although Exchange 2000 Enterprise edition removes the 16-gigabyte (GB) limit on an individual mailbox store, there are practical limits for backing up and restoring databases. Microsoft recommends that you use a 50-GB limit (approximately) for a single mailbox store.
•	Public folders are often used as archives; therefore, they tend to fill up eventually unless controls are implemented.
•	You can configure expiration policies on public folders to delete postings that are older than a certain age. However, this procedure is not appropriate for certain types of public folders, such as those folders that store contact details.
•	You may want to configure limits on a typical public folder that is used for simple posts to 20 megabytes (MB) and the limits on an archive folder to 100 MB. However, you may not want to configure limits on a Contacts folder (to make the space unlimited).
•	Like mailbox limits, you configure public folder limits on the public folder store; however, you can configure individual public folder limits to override the limits that you set on the store.
•	To perform an in-place restore, Microsoft recommends that your disks have at least as much free space as the size of the database itself plus at least 10 percent. For example, a 35-GB database runs on an 80-GB partition.
•	Remember that the deleted item retention time also affects the size of a public folder store because items are not actually deleted until after the deleted item retention time has expired.