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| Oracle Solaris Cluster Geographic Edition Data Replication Guide for EMC Symmetrix Remote Data Facility

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## Forcing a Takeover on a System That Uses SRDF Data Replication

Perform a takeover when applications need to be brought online on the secondary cluster regardless of whether the data is completely consistent between the primary volume and the secondary volume. The information in this section assumes that the protection group has been started.

The following steps occur after a takeover is initiated:

- If the former primary cluster, `cluster-paris`, can be reached and the protection group is not locked for notification handling or some other reason, the application services are taken offline on the former primary cluster.

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

- Data volumes of the former primary cluster, `cluster-paris`, are taken over by the new primary cluster, `cluster-newyork`.

  Note - This data might be inconsistent with the original primary volumes. After the takeover, data replication from the new primary cluster, `cluster-newyork`, to the former primary cluster, `cluster-paris`, is stopped.

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

For more details about takeover and the effects of the `geopg takeover` command, see Appendix C, Disaster Recovery Administration Example, in Oracle Solaris Cluster Geographic Edition System Administration Guide.

For details about the possible conditions of the primary and secondary cluster before and after takeover, see Appendix D, Takeover Postconditions, in Oracle Solaris Cluster Geographic Edition System Administration Guide.

The following sections describe the steps you must perform to force a takeover by a secondary cluster.

- Validations That Occur Before a Takeover

- Results of a Takeover From a Replication Perspective

- How to Force Immediate Takeover of SRDF Services by a Secondary Cluster

### Validations That Occur Before a Takeover

When a takeover is initiated by using the `geopg takeover` command, the data replication subsystem runs several validations on both clusters. These step are conducted on the original primary cluster only if the primary cluster can be reached. If validation on the original primary cluster fails, the takeover still occurs.

First, the replication subsystem checks that the SRDF device group is in a valid aggregate RDF pair state. The SRDF commands that are used for the takeover are described in the following table.

Table 3-2 SRDF Takeover Validations on the New Primary Cluster

Aggregate RDF Pair State | Protection Group Local Role | SRDF Takeover Commands That Are Run on `cluster-newyork`
--- | --- | ---
`FailedOver` | Primary | `symrdf $option $dg write_disable r2` `symrdf -g dg suspend` `symrdf $option $dg rw_enable r1`
`FailedOver` | Secondary | No command is run.
`Synchronized`, `Suspended`, `R1 Updated`, `Partitioned` | All | `symrdf -g dg failover`

### Results of a Takeover From a Replication Perspective

From a replication perspective, after a successful takeover, the `Local-role` property of the protection group is changed to reflect the new role, regardless of whether the application could be brought online on the new primary cluster as part of the takeover operation. On `cluster-newyork`, where the protection group had a `Local-role` of `Secondary`, the `Local-role` property of the protection group becomes `Primary`. On `cluster-paris`, where the protection group had a `Local-role` of `Primary`, the following might occur:

- If the cluster can be reached, the `Local-role` property of the protection group becomes `Secondary`.

- If the cluster cannot be reached, the `Local-role` property of the protection group remains `Primary`.

If the takeover is successful, the applications are brought online. You do not need to run a separate `geopg start` command.

| Caution - After a successful takeover, data replication between the new primary cluster, `cluster-newyork`, and the old primary cluster, `cluster-paris`, is stopped. If you want to run a `geopg start` command, you must use the `-n` option to prevent replication from resuming.

## How to Force Immediate Takeover of SRDF Services by a Secondary Cluster

Before You Begin

Before you force the secondary cluster to assume the activity of the primary cluster, ensure that the following conditions are met:

- Geographic Edition software is up and running on the cluster.

- The cluster is a member of a partnership.

- The `Configuration` status of the protection group is `OK` on the secondary cluster.

1. Log in to a node in the secondary cluster.

   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 takeover.

       # geopg takeover [-f] protectiongroupname

   `-f`

     Forces the command to perform the operation without your confirmation

   protectiongroupname

     Specifies the name of the protection group

Example 3-2 Forcing a Takeover by a Secondary Cluster

This example forces the takeover of `srdfpg` by the secondary cluster `cluster-newyork`.

The `phys-newyork-1` cluster is the first node of the secondary cluster. For a reminder of which node is `phys-newyork-1`, see Example Geographic Edition Cluster Configuration in Oracle Solaris Cluster Geographic Edition System Administration Guide.

    phys-newyork-1# geopg takeover -f srdfpg

Next Steps

For information about the state of the primary and secondary clusters after a takeover, see Appendix D, Takeover Postconditions, in Oracle Solaris Cluster Geographic Edition System Administration Guide.

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