Managing Serviceguard Extension for SAP on Linux (IA64 Integrity and x86_64), February 2008

Step-by-Step Cluster Conversion
Database Configuration
Chapter 3 165
Database Configuration
This section deals with additional database specific installation steps
and contains the following:
• Additional Steps for Oracle
• Additional Steps for MaxDB
Additional Steps for Oracle
The Oracle RDBMS includes a two-phase instance and crash recovery
mechanism that enables a faster and predictable recovery time after a
crash.
The instance and crash recovery is initiated automatically and consists
of two phases:
Roll-forward phase: Oracle applies all committed and uncommitted
changes in the redo log files to the affected data blocks. Following
parameters can be used to tune the roll forward phase:
• The parameter RECOVERY_PARALLELISM controls the number of
concurrent recovery processes.
• The parameter FAST_START_IO_TARGET controls the time a crash /
instance recovery may take. Use this parameter to make crash /
instance recovery predictable.
Roll-back phase: Oracle applies information in the rollback segments to
undo changes made by uncommitted transactions to the data blocks.
Following parameters can be used to tune the roll-back phase:
• Fast-Start On-Demand rollback: with this feature Oracle
automatically allows new transactions to begin immediately after
the roll forward phase of recovery completes. This means that the
database will be available again right after the completion of phase
one roll-forward. This means that there will be no long waits until
long running transactions are rolled back.
• Fast-Start Parallel Rollback: configure the
FAST_START_PARALLEL_ROLLBACK parameter to roll-back set of
transaction in parallel. This parameter is similar to the
RECOVERY_PARALLELISM parameter for the roll-forward phase.