Managing Serviceguard Extension for SAP Version B.05.10, September 2010

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.
All these parameters can be used to tune the duration of Instance / Crash recovery.
The following steps have to be performed in order to adjust the Oracle RDBMS setting to the
HA configuration.
Logon as root to the primary host of the database where the package is running in debug mode.
Oracle Database Step: OR850
Perform the following step as <sid>adm
To ensure that a database that crashed during an online backup starts correctly after the crash,
all data files that were in begin backup state need to be altered with an end backup statement.
Adjust the required steps in /sapmnt/<SID>/exe/startdb.
Change the following code within the /sapmnt/<SID>/exe/startdb file. The sample code
that is to be inserted for different Oracle releases can be found in the files:
/opt/cmcluster/sap/SID/startdb.sqlplus and
/opt/cmcluster/sap/SID/startdb.svrmgrl.
#
# Startup the database without changing the ARCHIVELOG state
#
echo "connect internal;" > $SRVMGRDBA_CMD_FILE
echo "startup;" >> $SRVMGRDBA_CMD_FILE
echo "exit;" >> $SRVMGRDBA_CMD_FILE
eval $SRVMGRDBA command=@$SRVMGRDBA_CMD_FILE >> $LOG 2>&1
Oracle Database Step: OR860
Perform the following steps as ora<sid>.
Configure the listener to listen on the relocatable name of the database package. To do this,
change all references from <local> to the relocatable name <relocdb> in the files on the shared
volume group. Be careful if these files were customized after the SAP installation. Example:
$ORACLE_HOME/network/admin/listener.ora
$ORACLE_HOME/network/admin/tnsnames.ora
When using Oracle 10g:
98 Step-by-Step Cluster Conversion