Scanning

The process of inventorying the virtual directories (and the physical directories pointed to by the virtual directories) to determine which documents should be indexed is called scanning. By default, all readable virtual directories are indexed. If some readable virtual directories should not be indexed, make sure the Index this directory check box is cleared in the Properties dialog box for that virtual directory. To gain access to this dialog box, in Internet Service Manager, select the virtual directory that you do not want indexed. On the Action menu, select Properties. Clear the Index this directory check box.

This section discusses the two types of scans and tells how to force a scan:

• Full Scan
• Incremental Scan
• Forcing a Scan from Administration Pages

You do not need to force a full scan or an incremental scan, because Index Server automatically detects what type of scan to do and does it without user intervention.

Full Scan

In a full scan, all the documents in the directories that are inventoried are added to the list of documents to be filtered. A full scan is performed the first time a directory is added to the list of indexed directories. A full scan is also performed as part of recovery if a serious error occurs.

Incremental Scan

In an incremental scan, only the documents that were modified since the last time they were filtered are added to the list of documents to be filtered. On startup of Index Server, an incremental scan is performed on all the indexed directories. This allows Index Server to determine which files were modified when it was not running.

During normal operation of Index Server, all changes to the documents in the indexed directories are automatically tracked if the indexed directories are on computers running Windows NT. Indexed directories are the set of all directories in the indexed virtual directories. Some file servers, such as Novell NetWare and Microsoft® Windows® 95 file server, do not support change notification. When a virtual directory points to a remote share that does not support change notification, Index Server does periodic scans of that share. The frequency of these periodic scans is controlled by the registry setting ForcedNetPathScanInterval.

Sometimes an incremental scan is also performed if the system loses change notifications. This can happen if the update rate of documents is very high and the buffer used to get change notifications from Windows NT overflows.

Forcing a Scan from Administration Pages

You can force either a full scan or an incremental scan on any of the indexed virtual directories by choosing the Force scan virtual directories option from the administration page. This will show the list of virtual directories. By default, no scan will be selected for any of the virtual directories. You can select the appropriate type of scan for the virtual directory and click Submit.

You should force a full scan after installing a new filter, removing a filter, or repairing a filter's registration information. Do not wait for the periodic scan on a remote virtual directory. Queries will continue to return documents, but query speed may slow down during the scanning and filtering.

For more information about forcing a scan, see Forcing a Scan.

Note   Forcing a full scan results in all the files in a scope being refiltered, which can take a long time.

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