Migrating Services That Use SRDF Data Replication With a Switchover

Perform a switchover of an SRDF protection group when you want to migrate services to the partner cluster in an orderly fashion. Basic Geographic Edition operations such as geopg switchover, perform a symrdf swap operation. The symrdf swap operation requires significantly more time for static RDF than dynamic RDF. Therefore, you might need to increase the value of the timeout property of the protection group when using static RDF.

A switchover consists of the following:

• Application services are brought offline on the former primary cluster, cluster-paris.

  For a reminder of which cluster is cluster-paris, see Example Geographic Edition Cluster Configuration in Oracle Solaris Cluster Geographic Edition System Administration Guide.

• The data replication role is reversed and now continues to run from the new primary, cluster-newyork, to the former primary, cluster-paris.

• Application services are brought online on the new primary cluster, cluster-newyork.

This section contains information about the following topics:

• Validations That Occur Before a Switchover

• Results of a Switchover From a Replication Perspective

• How to Switch Over an SRDF Protection Group From Primary to Secondary

Validations That Occur Before a Switchover

When a switchover is initiated by using the geopg switchover command, the data replication subsystem runs several validations on both clusters. The switchover is performed only if the validation step succeeds on both clusters.

First, the replication subsystem checks that the SRDF device group is in a valid aggregate RDF pair state. Then, it checks that the local device group type on the target primary cluster, cluster-newyork, is RDF2. The symrdf -g device-group-name -query command returns the local device group's state. These values correspond to a RDF1 or RDF2 state. The following table describes the SRDF command that is run on the new primary cluster, cluster-newyork.

Table 3-1 SRDF Switchover Validations on the New Primary Cluster

Results of a Switchover From a Replication Perspective

After a successful switchover, at the data replication level the roles of the primary and secondary volumes have been switched. The pre-switchover RDF1 volumes become the RDF2 volumes. The pre-switchover RDF2 volumes become the RDF1 volumes. Data replication continues from the new RDF1 volumes to the new RDF2 volumes.

The Local-role property of the protection group is also switched regardless of whether the application could be brought online on the new primary cluster as part of the switchover operation. On the cluster on which the protection group had a Local role of Secondary, the Local-role property of the protection group becomes Primary. On the cluster on which the protection group had a Local-role of Primary, the Local-role property of the protection group becomes Secondary.

How to Switch Over an SRDF Protection Group From Primary to Secondary

Before You Begin

For a successful switchover, data replication must be active between the primary and the secondary clusters and data volumes on the two clusters must be synchronized.

Before you switch over a protection group from the primary cluster to the secondary cluster, ensure that the following conditions are met:

• The Geographic Edition software is up and running on the both clusters.

• The secondary cluster is a member of a partnership.

• Both cluster partners can be reached.

• The protection group is in the OK state.

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Caution - If you have configured the Cluster_dgs property, only applications that belong to the protection group can write to the device groups specified in the Cluster_dgs property.

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1. Log in to a cluster node.

   You must be assigned the Geo Management RBAC rights profile to complete this procedure. For more information about RBAC, see Geographic Edition Software and RBAC in Oracle Solaris Cluster Geographic Edition System Administration Guide.

2. Initiate the switchover.

   The application resource groups that are a part of the protection group are stopped and started during the switchover.

   # geopg switchover [-f] -m newprimarycluster protectiongroupname

   -f

   Forces the command to perform the operation without asking you for confirmation

   -m newprimarycluster

   Specifies the name of the cluster that is to be the new primary cluster for the protection group

   protectiongroupname

   Specifies the name of the protection group

Example 3-1 Forcing a Switchover From Primary to Secondary

This example performs a switchover to the secondary cluster.

# geopg switchover -f -m cluster-newyork srdfpg