Oracle DataGaurd

DataGaurd
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Log Transport Services:

Log Apply Services:(Managed Recovery Mode , Read-Only Mode)
alter system set Log_archive_trace = integer ;

Remote File Service (RFS)
Archiver (ARCn)
Managed Recovery Process (MRP)

Start the standby instance
1 , startup nomount;
2 , alter database mount standby database;

Initiating Log Apply Services
Log apply services can run as a foreground session or as a background process with
control options such as CANCEL, FINISH, TIMEOUT, DELAY, DISCONNECT, and PARALLEL.

alter database recover managed standby database;
alter database recover managed standby database disconnect from session;

Monitoring the Recovery Process :
v$managed_standby

Controlling Managed Recovery Mode :
To control the managed recovery operation, use the TIMEOUT, CANCEL, NODELAY, DELAY, NEXT,
PARALLEL, FINISH, EXPIRE, and DISCONNECT control options.
< cancel , cancel immediate , cancel nowait >
< disconnect , disconnect [from session] >
< EXPIRE : This means that the value of the EXPIRE control option is the earliest amount of time that the
managed recovery operation will terminate, but it could be significantly later than the specified value. >

v$archived_log
v$archive_dest_status

Read-Only Mode
1 , startup nomount;
2 , alter database mount standby database;
3 , alter database open read only;

1 , alter database recover managed standby database cancel;
2 , alter database open read only;

To move the standby database from read-only mode back to managed recovery mode :
1 , Terminate all active user sessions on the standby database;
2 , Restart log apply services : alter database recover managed standby database;