By user13342577 on Jan 15, 2015
Another new feature of Oracle Solaris Cluster Geographic Edition
A few weeks ago I wrote about a new feature for Geographic Edition: DR Orchestration, which we added in Oracle Solaris Cluster 4.2. With the latest update to 4.2, SRU1, we've completed the testing of another Geographic Edition feature which can make DR Orchestration even more useful - we can now support Oracle Data Guard replication control for a remote database.
As I described before, a multigroup can combine several protection groups so that they can be switched together in a coordinated manner. That enables a service constructed out of multiple tiers, on multiple clusters, to be managed as a unit.
Since each tier is represented by a protection group it might seem necessary that each tier be running Oracle Solaris Cluster, which could be inconvenient if one of the tiers is running only an Oracle RAC database. There is no absolute requirement to use Oracle Solaris Cluster in that configuration; the systems might not be running any cluster software, or perhaps running Oracle RAC Clusterware. An example of such a configuration is the Oracle SuperCluster Engineered System.
In practice, however, we can use some features of Oracle Solaris Cluster and the Oracle Database to include such a tier in an orchestrated Geographic Edition configuration. The two features we're using are:
- The Oracle Solaris Cluster data service for Oracle External Proxy (HA for Oracle External Proxy)
- Remote database connectivity
HA for Oracle External Proxy
This is a data service which can be used to reflect the status of an Oracle database which is running on a remote system, so that local Oracle Solaris Cluster resources and resource groups can associate dependencies with it. You can find more information about it at: http://docs.oracle.com/cd/E39579_01/html/E52343/index.html
Remote Database Connectivity
This is a standard feature of the Oracle Database. A service name that is configured in the TNSNAMES.ORA file can identify a database that is running on a remote system, so that control operations from local sqlplus and dgmgrl (Data Guard broker) commands will operate on the remote database instance. To take advantage of this you don't even need to install a full Oracle database locally, you can just install the Oracle Database Client software, see: http://docs.oracle.com/database/121/SSCLI/toc.htm
Put these together, and...
By using these two features together you can now create a local Geographic Edition protection group (PG) that uses Oracle Data Guard replication, but which manages a database instance on a remote system. You just need to provide the name of a resource group that contains an external proxy resource, instead of an Oracle RAC or failover database resource. As far as the cluster configuration is concerned, this behaves just like an ordinary local protection group, and so it can be included in a multigroup as part of a DR Orchestration configuration. When you switch over that multigroup, the software will contact all the systems configured in the protection group, local and remote.
Now you can fully orchestrate all tiers of a service and control them from a system that is part of an Oracle Solaris Cluster configuration, even if the database tier is on a system that isn't running Oracle Solaris Cluster.