Dataguard Background Process
The services
required on the primary database are:
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.
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.
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.
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:
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.
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.
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).
(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.
Recovery Process (MRP) –
Applies archive redo log information to the standby database.