Converting a standard cluster to a linked cluster

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In PowerHA® SystemMirror® Version 7.2.6, or later, existing users can migrate a data center from the local site to the cloud environment to use the Geographic Logical Volume Manager (GLVM) features.

To convert an existing standard cluster to a linked cluster, add new node at the remote site (secondary site) and add all the existing cluster nodes at the local site (primary site). You must stop all cluster services during cluster conversion.

The following figure shows an example conversion of a standard cluster to a linked cluster. The standard cluster in the following example consists of two nodes, NodeA, NodeB, and repository disk hdisk1. After conversion, a linked cluster is created which consist of an existing standard cluster at the local site, and a new node NodeC and a new repository disk hdisk2 at the remote site.

Figure 1. Standard cluster to a linked cluster conversion

To convert an existing cluster to a linked cluster, complete the following steps:

Take a snapshot of an existing standard cluster and save it. For instruction about creating a snapshot of the cluster, see Creating a snapshot of the cluster configuration.
To change the standard cluster type, run the following command.
```
# clmgr modify cluster TYPE=LC
```
To create a local site and to add all nodes of the standard cluster to it, run the following command:
```
# clmgr add site <local site name> NODES=<All nodes part of existing standard cluster>
```
For example, to create a local site, SiteA and to add two cluster nodes, NodeA and NodeB, run the following command:
```
clmgr add site SiteA NODES=NodeA,NodeB
```
To create a remote site with a new node and a new repository disk, run the following command:
```
# clmgr add site <remote site name> NODES=<Remote site node>
         REPOSITORIES=<remote site repository disk name>
```
For example, to create a remote site, SiteB with a new node NodeC, and a new repository disk hdisk2, run the following command:
```
clmgr add site SiteB NODES=NodeC REPOSITORIES=hdisk2
```
To synchronize the linked cluster, run the following command:
```
# clmgr sync cluster
```
To verify conversion of the standard cluster to a linked cluster, run the following command:
```
# clmgr query cluster
```

Note: In case of conversion failure, restore the previous cluster configuration. For instruction, see Restoring the cluster configuration from a snapshot.