Microsoft Exchange Server 2007 Administrators Pocket Consultant Second Edition

Content indexing is a built-in Exchange feature. Every Exchange server in your organization supports and uses some type of indexing. To manage indexing more effectively, use the techniques discussed in this section.

Understanding Indexing

Content indexing enables fast searches and lookups through server-stored mailboxes and public folders. Exchange Server supports two types of indexing:

• Standard indexing

• Full-text indexing

The Exchange Server storage engine automatically implements and manages standard indexing. Standard indexing is used with searches for common key fields, such as message subjects. Users take advantage of standard indexing every time they use the Find feature in Microsoft Office Outlook. With server-based mail folders, standard indexing is used to quickly search To, From, Cc, and Subject fields. With public folders, standard indexing is used to quickly search From and Subject fields.

As you probably know, users can perform advanced searches in Outlook as well. In Outlook, all they need to do is select the Advanced Find option from the Tools menu, enter their advanced search parameters, and then click Find Now. When Exchange Server receives an advanced query without full-text indexing, it searches through every message in every folder. This means that as Exchange mailboxes and public folders grow, so does the time it takes to complete an advanced search. With standard searching, Exchange Server is unable to search through message attachments.

With full-text indexing, Exchange Server builds an index of all searchable text in a particular mailbox or public folder database before users try to search. The index can then be updated or rebuilt at a predefined interval. Then, when users perform advanced searches, they can quickly find any text within a document or attachment.

The drawback of full-text indexing is that it's resource-intensive. As with any database, creating and maintaining indexes requires CPU time and system memory, which can affect Exchange performance. Full-text indexes also use disk space. A newly created index uses approximately 20 percent of the total size of the Exchange database. This means that a 1-GB database would have an index of about 200 megabytes (MB).

Each time you update an index, the file space that the index uses increases. Don't worry-only changes in the database are stored in the index updates. This means that the additional disk space usage is incremental. For example, if the original 1-GB database grew by 50 MB, the index would use about 210 MB of disk space (200 MB for the original index and 10 MB for the update).

Managing Full-Text Indexing

Unlike earlier releases of Exchange, Exchange Server 2007 doesn't allow administrators to control how indexing works. With Exchange Server 2007, the Microsoft Search (Exchange) service provides the full-text indexing of databases, and Microsoft Exchange Search provides search services. These services provide automated full-text indexing.

Full-text indexes are stored as part of the Exchange system files. Because of this, whatever folder location you use for Exchange system files will have a CatalogData- <GUID> subfolder for each storage group, which contains all the full-text indexing data for the related storage group and all its related databases. By default, you'll find full-text index files for the First Storage Group in the %SystemDrive%∖Program Files ∖Microsoft∖Exchange Server∖Mailbox∖First Storage Group∖CatalogData-<GUID> folder, the index files for the Second Storage Group in the %SystemDrive%∖Program Files∖Microsoft∖Exchange Server∖Mailbox∖Second Storage Group∖CatalogData- <GUID> folder, and so on.

As part of the recovery process for a mailbox or public folder database, you may want to rebuild the related full-text index catalog to ensure it is current. You may also want to rebuild the full-text index after you've made substantial changes to a database or if you suspect the full-text index is corrupted.

You can rebuild an index manually at any time. Exchange Server rebuilds an index by re-creating it. This means that Exchange Server takes a new snapshot of the database and uses this snapshot to build the index from scratch. To manually rebuild an index, follow these steps:

1. Log on to the Exchange server using an account with administrator privileges.

2. Open a command prompt.

3. At the command prompt, stop the Microsoft Exchange Search service by typing net stop MsExchangeSearch.

4. Use Windows Explorer to delete the CatalogData-<GUID> subfolder, which contains the full-text index for the database.

5. At the command prompt, start the Microsoft Exchange Search service by typing net start MsExchangeSearch.