Tuesday, September 13, 2016
Dataguard Background Process
The services required on the primary database are:
•Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. It can also create local archived redo logs and transmit online redo to standby databases.
•Archiver Process (ARCn) - One or more archiver processes make copies of online redo logs either locally or remotely for standby databases.
•Fetch Archive Log (FAL) Server - Services requests for archive redo logs from FAL clients running on multiple standby databases. Multiple FAL servers can be run on a primary database, one for each FAL request.
The services required on the standby database are:
•Fetch Archive Log (FAL) Client - Pulls archived redo log files from the primary site. Initiates transfer of archived redo logs when it detects a gap sequence.
•Remote File Server (RFS) - Receives archived and/or standby redo logs from the primary database.
•Archiver (ARCn) Processes - Archives the standby redo logs applied by the managed recovery process (MRP).
•Managed Recovery Process (MRP) - Applies archive redo log information to the standby database.