The background writers and before-image manager are processes that improve performance by continually performing overhead functions in the background. The background writers and before-image manager are only available for Enterprise systems. You must start these processes manually.

There are three types of background writer: the asynchronous page writer (APW), the before-image writer (BIW), and the after-image writer (AIW). The before-image manager (BIM) also runs in the background.

The following sections explain how to start up and shut down the background writers and the before-image manager. See Manage Performance for detailed information about background writers.