Exchange 2000 Server can create and manage full-text indexes to enable fast searches and lookups. Earlier versions of Exchange search every message in every folder, so search times increase as databases expand. With full-text indexing, every word in a database is indexed, making faster searching possible. Outlook users can search for documents in Exchange as easily as they can search for e-mail messages. Attachment text can also be searched in documents of the following types: .doc, .xls, .ppt, .html, .htm, .asp, .txt, and .eml (embedded MIME messages). Binary attachments are not indexed.
Full-text indexing is enabled on the Exchange server to allow established clients to use the feature. When full-text indexing is enabled, all MAPI clients can use it. When it is not enabled, MAPI clients can perform only the standard character-based search of the message body. Only MAPI and IMAP4 clients can use full-text indexing.
Indexing is a resource-intensive feature that takes considerable CPU cycles. Indexing gigabytes of data can take hours or days, providing another reason to use multiple small databases. Index builds should be scheduled for times when the server is not already overtaxed.
Index storage requires approximately 20% of the disk space of the database.
Use server-level backups to backup indexes, because individual indexes cannot be backed up.
Tip When creating a new index for an Information Store that is 6 GB or less, you should populate the index overnight and set the resource usage to Maximum. For an Information Store that is 6 GB or more, you should populate the index over a weekend and set the resource usage to Maximum.
After the initial population, you can update an index incrementally. For an Information Store with a significant user load and high memory usage, set the resource usage to Minimum. Incremental updates may take longer to complete because users' requests are given priority over index population. However, users can still search the index while it is being updated.
If the Information Store is 6 GB or smaller, you can perform incremental updates hourly. If the Information Store is larger than 6 GB, or the server has high memory usage, you may want to update less frequently.
Not every instance of a message in every database is indexed. The message is indexed only once.