Building Disaster Recovery Serviceguard Solutions Using Metrocluster with 3PAR Remote Copy

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Configuring SGeRA cluster interconnect subnet monitoring
SGeRAC provides a feature to monitor the Oracle Clusterware interconnect subnet and to ensure
that at least one RAC instance survives when a failure takes down the entire interconnect subnet
in the cluster.
To configure this feature, the interconnect subnet must be specified in a separate MNP package
using the CLUSTER_INTERCONNECT_SUBNET package attribute. The Clusterware MNP package
for the Clusterware sub-cluster must have a dependency specified on this interconnect MNP package.
For more information on network planning for Oracle Clusterware communication, see the latest
edition of Using Serviceguard Extension for RAC manual available at http://www.hp.com/go/
hpux-serviceguard-docs-> HP Serviceguard Extension for RAC.
The Oracle Clusterware interconnect subnet for a site Clusterware sub-cluster is a subnet spanning
only the nodes in that site (it is not required to route it across the sites). The interconnect subnets
at each site is packaged in a separate MNP package.
To configure the SGeRAC Cluster Interconnect packages:
1. Create a package directory on all nodes in the site.
# mkdir -p /etc/cmcluster/pkg/sfo_ic
2. Create a package configuration file and control script file. Use site-specific names for the files.
You must follow the legacy package creation steps.
# cmmakepkg -p sfo_ic.conf
# cmmakepkg -s sfo_ic.cntl
3. Specify a site-specific package name in the package configuration file.
4. Specify only the nodes in the site for the node_name parameter.
5. Specify the package type as MULTI_NODE.
6. Specify the SGeRAC Cluster Interconnect as CLUSTER_INTERCONNECT_SUBNET.
7. Save and apply the package configuration file.
# cmapplyconf –P sfo_ic.conf
Configuring and administration restrictions
The following are the configuration and administration restrictions that apply to SADTA
configurations for application workloads:
• Only two sites can be configured in Metrocluster configuration.
• All Serviceguard restrictions that apply to site configurations also apply to configuring
Metrocluster for RAC.
• For a RAC database that is configured in Metrocluster for RAC, the redundant database
configuration at each site sub-cluster must have same number of instances.
• When using VERITAS CVM, each CVM disk group must be configured with a Modular package
at both sites.
Failure scenarios in Metrocluster for RAC
This section elaborates on 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 that monitors the RAC MNP package detects that the RAC MNP has failed. The database
failure is handled based on the manner in which the RAC MNP stack is configured with the Site
Controller Package.
94 Configuring Oracle RAC in SADTA