Home > Storage > PowerStore > Data Protection > Dell PowerStore: Metro Volume > Metro Volume operations
This section describes the operations in PowerStore Manager for a Metro Volume. You can run an operation for a Metro Volume in various screens. Apart from the actions to Configure and End Metro Volume, which are also available in the Volumes overview screen, the operations are available in Volume details view. This view is available in Volumes > [Volume Name] > Volume details > Protection > Metro Volume. The operations are also available in the Metro session overview (Protection > Metro). When an operation with impact on host I/O is supposed to be performed, a dialog box appears which shows a detailed description of the effective Metro Volume state after the operation is executed.
You can start a new Metro Volume configuration in Volumes Overview or in the Volume details view in the subtab for Protection > Metro Volume. The wizard only requires the remote system to define the peer PowerStore cluster. (See more details about the remote system and replication protocol in the document PowerStore: Replication Technologies.) When the peer is a multi-appliance cluster, there is an extra field to specify the appliance. Without selecting an appliance, PowerStore balances the Metro Volumes across available appliances. When no migration or replication is configured for the volume, configuring Metro Volume is possible in any state of a standard volume. When a Metro Volume is configured, a Metro replication session is created. The Metro replication session initiates the initial synchronization for the Volume.
These operations swap the preferred role for a Metro Volume and could be performed once a Metro Volume reaches the state Operating normally (Active-Active). Changing the role could be required to set the same role for volumes relating to the same application to a single PowerStore cluster. If there is a failure scenario, all volumes of the same application could be affected by polarization. Another use case would be changing the role before planned maintenance on one of the Metro Volume sites or pausing a Metro Volume.
To modify some Metro Volume properties, you must pause a Metro Volume. The following operations require a Metro Volume to be paused: volume resize, volume restore from snapshot, volume refresh from an object within the clone family (clone or snapshot), and volume rename.
Pausing a Metro Volume could also be used during planned maintenance. Be aware that pausing a Metro Volume disables host I/O on the non-preferred side of a Metro Volume. For non-uniform host configuration, we recommended ensuring that hosts with running VMs are using the preferred volume to avoid an unwanted restart of VMs.
The Metro Volume data synchronization between PowerStore-A and PowerStore-B will be paused. On the preferred system, production access will continue for applications. The local protection policy will remain active. On the non-preferred system, production access will remain disabled for hosts and applications. The local protection policy will remain paused.
This operation resumes a paused Metro Volume and starts switching into an active-active state. The host writes and snapshots created on the preferred volume while the metro volume was paused, will be synchronized to the peer system.
A promote action enables host and production access on a non-preferred Metro Volume and is only available in states Paused and Fractured. A promote action can result in data corruption if the remote system is online and serving I/O. If only the connection between the current PowerStore system and the remote PowerStore system is down, verify that the remote system is no longer online.
After the promote action, production access will be enabled for hosts and applications on the current system. The local protection policy becomes enabled, and snapshot creation resumes.
A demote action disables host and production access on a preferred Metro Volume in the paused state. To prevent data corruption, the demote action is restricted when there is network connectivity between the two PowerStore systems and the remote Metro Volume also has production access. Once the demote operation completes, the non-preferred metro volume can be promoted.
After the demote action, production access will be disabled for hosts and applications. The local protection policy will be disabled, and scheduled snapshot creation will be halted.
This operation ends a Metro Volume replication session for the volume. The wizard to end this session provides two options:
| Status | Reconfig allowed | Modify role | Promote | Demote | Pause | Resume | End Metro |
On preferred | Operating Normally |
| Yes |
|
| Yes |
| Yes |
Paused | Yes |
|
| Yes |
| Yes | Yes | |
Fractured | Yes |
|
| Yes | Yes |
| Yes | |
Synchronizing |
|
|
|
| Yes |
| Yes | |
On non-preferred | Operating Normally |
| Yes |
|
| Yes |
| Yes |
Paused | Yes |
| Yes |
|
| Yes | Yes | |
Fractured | Yes |
| Yes |
| Yes |
| Yes | |
Synchronizing |
|
|
|
| Yes |
| Yes |