Hello Friends,
I this post we will discuss the various background process in
dataguard with this easy-to-understand explanation.
so let's get started.
·
What are background processes:
Background processes are the demons used by the database to perform various activities
for example in case of dataguard below are the process that are used
· MRP0 (Managed Standby
Recovery Process):
MRP0 coordinates the read and apply the process of
redo in a physical standby database.
·
RFS (Remote File Server):
RFS is responsible for receiving the redo data,
which is sent by the primary database to the standby database.
·
LSP0 (Logical Standby
Coordinator Process):
LSP0 Coordinates the SQL Apply processes, which
are the mining processes and application processes.
·
LSP1 (Logical Standby
Dictionary Build Process):
LSP1 is used on the logical standby databases
when a switchover or failover is in action.
·
LSP2 (Logical Standby Set
Guard Process):
LSP2 is used to operate Database Guard settings.
Database Guard specifies which objects will be protected for modification in a
logical standby database.
·
NSAn (Redo Transport NSA1
Process):
NSAn is used on the primary database to ship
redo data to the standby database when ASYNC mode is being used. There may be
multiple NSA processes such as NSA1 and NSA2.
·
NSSn (Redo Transport NSA1
Process):
NSSn is also used on the primary database to ship redo data to the standby database. However, only when the SYNC mode is being used.
·
DMON (Data Guard Broker
Monitor Process):
DMON process runs on every instance in a Data Guard
broker configuration. It communicates with the local database and DMON processes of
the remote databases. The broker-related requests and the monitoring
information are transferred on this communication channel.
·
FSFP (Data Guard broker
fast-start failover pinger process):
Is FSFP used for the management of fast-start failover status.
Switchover status column values meaning as follows:
Not Allowed : Primary or Standby database either its not allowed to switch-over.
Session Active : An active SQL sessions attached to the primary or standby database that need to be disconnected before the switchover operation.
Switchover Pending : Switchover request has been received but not processed.
Switchover Latent : Switch-over was in pending mode did not complete and went back to the primary database.
To Primary : No active sessions present which allowed to switch over to a primary database.
To Standby : No active sessions present which allowed to switch over to a standby database.
Recovery Needed : Standby DB, EOR - End of redo us still not recieved .
Hope This Help's.
Regards
Sultan Khan
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