Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

Creating consistency group

A consistency group is simultaneous snapshots of multiple virtual disks, thus ensuring consistent copies of a group of virtual disks. Each virtual disk that belongs to a consistency group is referred to as a member virtual disk. When you add a virtual disk to a consistency group, the system automatically creates a snapshot group that corresponds to this member virtual disk.

1. From the AMW, select the Storage & Copy Services tab.
2. Select Copy Services > Consistency Group > Create.
   The Consistency Group Settings window is displayed.
3. In the Consistency group name field, enter a unique name (30-character maximum) that best describes the member virtual disks that you want to add for this group.
   By default, the consistency group name is shown in the name text box as:CG + sequence-number

   In this example, CG (Consistency Group) is the prefix and sequence-number is the chronological number of the consistency group, and is incremented based on how many consistency groups currently exist.

4. Select if you want to add the member virtual disks to the consistency group now or later:
   • Select Add members now and then from the eligible member virtual disks, select the virtual disks that you want to add as members to the consistency group. If you choose this method, you must create a repository for each member of the consistency group. Go to step 5. You can click the Select all check box to add all the virtual disks displayed in the Eligible virtual disks table to the consistency group.
   • Select Add members later and then click Finish to create the consistency group without member virtual disks. Go to step 6.
   The Eligible virtual disks table shows only those virtual disks that are capable of being used in the consistency group. To be eligible to be a member of a consistency group, a virtual disk cannot be in a Failed state and must contain less than the maximum allowable number of associated snapshot groups.
5. Select how you want to create the repositories for each member in the consistency group.
   • Select Automatic and click Finish to create the repositories with the default capacity settings. This option is the recommended one.
   • Select Manual and click Next to define the capacity settings for the repositories; and then click Finish to continue with the consistency group creation process. You can click Edit individual repository candidates to manually edit a repository candidate for each member virtual disk.
     NOTE: Use this option if you want to specify all the customizable settings for the repositories. The Manual method is considered advanced and only those who understand physical disk consistency and optimal physical disk configurations should use this method.
6. Click Finish.
   In the navigation tree, the consistency group and its properties are displayed under the Consistency Groups node.