Introduction to Data Guard
NY SIG Meeting
October 7th, 2003
(It’s my job)
Larry M. Carpenter
Senior Principal Consultant
Data Guard Development
Disaster Recovery Food Chain
So, just what is Data Guard?
“An application-transparent high-performance low-
impact asymmetrical online reliable Redo or SQL
level background standby database transaction
exchange utility capable of reporting, switchover
Data Guard helps you protect your Data.
– Takes your data and automatically puts it elsewhere
– Makes it available for Failover in case of failure.
The other capabilities are pure bonus.
– Switchover for Maintenance
– Off-loading Queries
Data Guard ‘Pyramid’
D a t a G u a r dPhysical and
Production / Primary
Broker and CLI
EM Data Guard
Data Guard comprises of two parts
– REDO APPLY (DR)
Maintains a physical, block for block copy of the
Production (also called Primary) database.
– SQL APPLY (Reporting)
Maintains a logical, transaction for transaction copy of
the Production database.
Data Guard Redo Apply: Best for DR
Physical Standby Database is a block-for-block copy of the primary database
Uses the database recovery functionality to apply changes
Can be opened in read-only mode for reporting/queries
Can also perform backup, offloading production database
The best solution for DR
Data Guard Broker
Sync or Async
DIGITAL DATA STORAGE
Data Guard SQL Apply
Logical Standby Database is an open, independent, active database
Contains the same logical information (rows) as the production database
Physical organization and structure can be very different
Can host multiple schemas
Can be queried for reports while logs are being applied via SQL
Can create a