Data guard Setup

Data guard Setup

Snapshot Standby

Standby can be converted to snapshot standby
uCan be opened in read-write mode (for testing)
uRedo transport continues
uRedo apply delayed
uStandby can subsequently be converted back to physical standby

uActive Data Guard
uSeparately licensed option
uUpdates applied to primary
uChanges can be read immediately on standby databases
uStandby database can be opened in read-only mode
uRedo can continue to be applied

uThree protection modes:
uMaximum protection - zero data loss
uRedo synchronously transported to standby database
uRedo must be applied to at least one standby before transactions on primary can be committed
uProcessing on primary is suspended if no standby is available

uMaximum availability - minimal data loss
uSimilar to maximum protection mode
uIf no standby database is available processing continues on primary

uMaximum performance (default)
uRedo asynchronously shipped to standby database
uIf no standby database is available processing continues on primary