Exchange Server Cookbook

Chapter 6. Mailbox and Public Folder Database Management

Introduction

Exchange uses a set of databases to store mail and public folder data. At a very basic level, Exchange is simply a highly specialized database management system. Understanding how to optimize your organization's use of Exchange databases and transaction logs will ensure that you get the best performance and reliability from your messaging infrastructure.

Storage Groups

Exchange 2000 introduced the concept of the storage group (SG): a set of databases (each one of which can contain mailbox or public folder data) that share a common set of transaction logs. The impetus behind this design is simple: you can mount or dismount individual databases, which means you can back up, restore, repair, defragment, or otherwise work with one database without affecting users whose mailboxes are in other databases. Exchange 2000 and Exchange Server 2003 Enterprise Edition servers can have up to four SGs, whether they're standalone or clustered, with up to five databases in each SG. The Standard edition of these products allows you to create one MAPI public folder database and one mailbox database (although you can create additional non-MAPI public folder stores, and even multiple SGs, if you like). Each of these databases is limited to 16 GB in size; Enterprise Edition databases don't have set size limits.

Exchange Server 2003 offers a special additional SG known as a recovery storage group (RSG); the RSG can be used to mount any ...