Global Mirror feature on IBM Storwize

Registering Global Mirror with Storwize

You can register a secondary storage for global mirror in PowerVC for a primary storage provider. You can perform this activity on the Storage details page of the user interface or through API. When you register a secondary storage, a default global mirror storage template is added to the Storage templates list. For API details, see Storage controller registration.

After setting up global mirror with PowerVC, when you create a volume using the Global Mirror storage template - the volume will be available in the primary storage and replicated on the secondary storage.

Once the volume is in a consistent synchronized state - the remote copy relationship is considered as stable; and in this state, the volumes on primary and secondary storage are similar. Refer to the States section for different states possible.

Retype and Delete operations on a volume with Global Mirror template

When a volume is retyped from a Global Mirror template to a non mirror template, the remote copy relationship is deleted at the storage backend. Also, the default behavior is to delete the replicated volume (or aux volume) on the secondary storage as well. Same is the case for deleting a volume with Global Mirror template. When a delete operation is performed on a volume with Global Mirror template - the remote copy relationship is deleted at the storage backend and the replicated volume (or aux volume) on the secondary storage is deleted as well.

PowerVC has introduced a CLI that helps you to change the default behavior of deletion of volumes on secondary storage when retype or delete of Global Mirror volume is performed. This is a system wide setting which affects all Global Mirror volumes managed in PowerVC. For details, see Commands.

Global Mirror with VM Recovery Manager (VMRM) for disaster recovery (DR)

PowerVC can work in coordination with VMRM for Global Mirror volumes for group operations on Global Mirror volumes. For details, see VM Recovery Manager DR.

By default, VMRM adds new volumes on IBM Storwize in a group (known as RCCG). For enabling group operations of these volumes from PowerVC, you can create a group type key in PowerVC with name - replication_enabled_vmrm and perform group operations like group clone.

Failover to secondary storage and failback operations for the virtual machine need to be planned using the VM Recovery Manager tool.

Limitation

Virtual machine snapshot/restore is not supported for Global Mirror volumes.