Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access EVA A.05.01

Starting the disaster tolerant Oracle RAC database with ASM in the Metrocluster
The procedure to start the disaster tolerant Oracle RAC database with ASM is identical to the
procedure for starting a complex workload in a Metrocluster. For more information on starting the
complex workload in the Metrocluster, see “Starting the complex workload in the Metrocluster”
(page 48).
Failure scenarios in Metrocluster for RAC
This sections describes the failure scenarios in Metrocluster for RAC.
Oracle RAC database Failure
When failures such as tablespace corruption, or errors arising out of insufficient storage space
occur, the RAC database instance processes on the nodes fail. When the Oracle RAC database
instance fails at a site, the RAC MNP package instance containing it also fails. The Site Controller
Package monitoring the RAC MNP package detects the RAC MNP failure. The database failure
is handled based on the manner in which the RAC MNP stack is configured with the Site Controller
Package.
When the RAC MNP package is configured as a critical_package, the Site Controller Package
considers only the RAC MNP package status to initiate a site failover. Since the RAC MNP package
fails when the contained RAC database fails, the Site Controller Package fails over to start on the
remote site node and initiates a site failover from the remote site.
When the RAC MNP package is configured as a managed_package along with other packages
in the stack, such as the CFS MP and CVM DG packages, the Site Controller Package considers
the status of all configured packages to determine a failure. When the RAC database fails, only
the RAC MNP package fails. All other managed packages continue to be up and running. As a
result, the Site Controller Package does not perform a site failover. The Site Controller Package
only logs a message in the syslog and continues to run on the same node where it was running
before the RAC database failed. You must intervene manually to restart the RAC database MNP
package.
Oracle RAC database instance failure
Certain error conditions in the run time environment of a node can cause the Oracle RAC database
instance on the node to fail. This causes the corresponding RAC MNP package instance on the
node to go down. The RAC MNP package continues to run with one less instance being up and
the Site Controller Package continues to monitor the RAC MNP stack.
However, if the failed RAC database instance is the last surviving instance, the RAC MNP package
fails in the cluster and stops. The Site Controller Package detects the failure and initiates a site
failover if the RAC MNP is configured as a critical_package.
Oracle RAC database Oracle clusterware daemon failure
The Oracle Clusterware is an essential resource for all RAC databases in a site. When the crsd
or evmd daemons are aborted on account of a failure, they are automatically restarted on the
node. When the cssd daemon is aborted on account of a failure on a node, the node is restarted.
The RAC MNP stack continues to run with one less instance on the site.
The Site Controller Package continues to run uninterrupted as long as there is at least one RAC
MNP instance running and the RAC MNP package has not failed. However, if the failed RAC
database instance is the last surviving instance on the site, when the node is restarted, it initiates
a failover of the Site Controller Package to the remote site. The Site Controller Package, during
startup at the remote site, will detect the failure and perform a site failover starting up the RAC
MNP stack configured in that site.
Administering Metrocluster for RAC
This section describes the procedures to administer Metrocluster for RAC.
126 Configuring Oracle RAC in SADTA