Dell PowerStore 9200T EMC PowerStore Protecting Your Data - Page 29

NOTE: If a metro volume was paused for a long time, synchronization may take a while due to data accumulation on the preferred system. If the non-preferred system was promoted, resuming the metro volume from the promoted non-preferred system synchronizes data from the promoted non-preferred system to the preferred. Steps 1. Select Protection > Metro. 2. Select the check box of the metro volume to resume and click Resume. The Resume Metro Volume dialog box is displayed. 3. Click Resume to confirm. Promote a metro volume Prerequisites The metro volume to promote must be in a Fractured or Paused state. About this task When the link between the two storage systems fails or when the non-preferred system is down, the synchronization between the systems is stopped and the metro volume becomes fractured. The preferred system remains active and continues to service I/Os. If the user is on the preferred system, no action is required and the systems synchronize when the issue is resolved. When a failure occurs on the preferred system, the synchronization between the systems is stopped and the metro volume becomes fractured. Both systems stop servicing I/Os. To be able to access the metro volume, the user must promote the metro volume on the non-preferred system to enable host and production access to it until the preferred system recovers. If the user verifies that the preferred system is available, the metro volume on the non-preferred system can be promoted with no implication. When the user is on the non-preferred system, it is not possible to know the status of the preferred system (whether the system is down or the link between the system is down). In this case, promoting the metro volume on the non-preferred system may result in a situation where both systems continue to service I/O but do not synchronize. Steps 1. Select Protection > Metro. The Metro page lists all the metro resources and makes it easy to evaluate all the impacted volume and prioritize promoting according to your considerations. NOTE: The metro status of the volume should be Fractured. 2. Click the status of the metro volume to display the Metro Volume page and click Promote. The Promote Metro Volume slide-out panel is displayed. NOTE: Before the promotion takes place, a snapshot of the metro volume is taken. 3. Verify that you understand the implication of promoting the metro volume in case the remote system is servicing I/Os and verify that the remote system is down if possible. 4. Select the confirmation checkbox at the bottom of the Promote Metro Volume slide-out panel, and select Promote. The promoted state of the volume is indicated in the Metro Volume Details section of the Metro Volume page. Demote a metro volume About this task When the preferred system runs out of storage space, the synchronization between the systems is stopped and the metro volume becomes fractured. Both systems stop servicing I/Os. In that case, the metro volume on the non-preferred system must be promoted to enable host and production access to it until the preferred system resolves the problem. To enable this state, the metro volume on the preferred system must be demoted first. Steps 1. Select Protection > Metro. Metro Protection 29