AP Components

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AP consists of the following components:

AP Daemon

ap_daemon(1M) runs on your Sun server and receives user requests via the AP commands executed on the server. The daemon acts as an intermediary between the commands and the AP Librarian, ap(7). It passes requests received via RPCs to the librarian by invoking ioctls. The actual work of maintaining the database is performed by the librarian.

AP Librarian

ap(7) manages the AP database and interacts with the meta-drivers as necessary. It receives requests via ioctls and acts on them by updating the database or calling entry points in the meta-drivers.

AP Meta-Drivers

The low-level capability for re-routing I/O accesses to alternate paths is implemented in the meta-drivers. The meta-drivers are: ap_dmd(7), ap_nmd(7), mle, mqe, mnf, mhi, and mbf

All application I/O requests that use the appropriate meta-disk go through a meta-driver that passes them to the physical device drivers. As a result, the meta-drivers can decide which physical path to use, whether a given path is no longer functioning, and so forth. The information on which the meta-drivers base their decisions comes from the AP Librarian and AP Database.

AP SSP Daemon

ap_ssp_daemon(1M) executes on the SSP and receives RPC requests from the AP Daemon whenever the AP database changes. This daemon is responsible for maintaining a file on the SSP containing alternate pathing information for booting.