Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access for P9000 and XP A.11.00

Figure 43 Recovery of a complex workload after primary cluster failure
Figure 42 (page 127) illustrates a complex workload with 3DC replication in a Multi-Hop Bi-Link
configuration. You can also have the 3DC replication in Multi-Target Bi-Link or Tri-Link configuration.
IMPORTANT: In this section, subsequent topics describe configuring complex workloads in 3DC
with SADTA using Oracle RAC as an example. These topics also explain how to configure volume
managers such as SLVM and LVM in this solution. Administrators or operators can configure any
other application as a complex workload in this solution. While using different applications, the
Oracle specific steps must be replaced or modified with the steps that are specific to the application.
Deploying Oracle RAC in a 3DC Solution using SADTA
An Oracle RAC database can be deployed in a 3DC solution for disaster recovery using SADTA.
In this architecture, a RAC database is configured as three RAC databases that are replicas of one
another; one at each site in the 3DC solution for disaster recovery. A Metrocluster must be configured
between two of the three sites. This cluster acts as a primary cluster in the Continentalclusters
environment. A Serviceguard cluster must be configured at the third site. This cluster acts as a
recovery cluster in the Continentalclusters environment.
To configure Oracle RAC in the 3DC solution, two Oracle CRS sub-clusters are created in the
primary cluster; one at each site in the primary cluster, and one CRS cluster is created in the
recovery cluster. The Oracle Clusterware software is installed at each site in the 3DC solution. The
CRS daemons at the sub-clusters are configured as a Serviceguard package using the HP
Serviceguard Extension for Oracle RAC Toolkit (delivered as part of the HP Serviceguard Extension
for Oracle RAC). The CRS Home is installed on a file system that is local to a site. The CRS voting
and OCR disks must not be configured for replication.
A RAC database is configured redundantly by configuring it at all three sites. The RAC database
processes, the disk groups, and file systems at each site are configured as a stack of inter-dependent
MNP packages. This stack of inter-dependent MNP packages is referred to as a RAC MNP stack.
The RAC database processes are packaged using the HP Serviceguard Extension for Oracle RAC
Toolkit (delivered as part of the HP Serviceguard Extension for Oracle RAC). The CVM DG MNP
and CFS MP MNP packages are created using HP Serviceguard Storage Management Suite (HP
SG SMS) commands for disk groups and cluster file systems that are used to store the database.
A Site Controller Package is created in the primary cluster to manage the RAC databases configured
in the primary cluster. This Site Controller Package provides robust site failover for a RAC database
128 Designing a Three Data Center Disaster Recovery Solution