The usage patterns for public folders vary from company to company. Some companies don't use public folders, some support discussion groups and news in public folders, and some deploy intensive workflow applications. If your organization supports large-scale public folder activity, this affects your system performance. But keep in mind that the public information store is separate from the private information store. It has its own database file. This means that you can maintain the public information store database files on a logical drive that is separate from the private information database for maximum random I/O performance. Likewise, you can maintain the public store database on a separate drive, although this is less likely to increase performance if you already have a stripe set for the database.
Many site administrators might want to provide Internet newsgroups and store this data in public folders for uniform user access. In such a case, the incoming news feeds can generate a large amount of write activity in the public store, so be sure to optimize the log drives.
Although the public and private stores are separate databases, a single instance of the database engine runs both. They also share the same memory buffers. If your organization experiences heavy use of public folders, you can improve performance by splitting the public folders onto separate servers. This reduces competition for computer resources, including buffers. A pool of public folder servers can also provide flexibility in load balancing.
Summary of Recommendations