Administrator Guide

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.
Manually creating a consistency group repository
During the creation of a consistency group, a consistency group repository is created to store the data for all the snapshot images
contained in the group. A consistency group's repository is created initially with one individual repository virtual disk.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 new snapshot group that corresponds to this member virtual disk. A consistency group repository must be created
for every member virtual disk in the consistency group to save the data for all the snapshot images contained in the group.
The Manual method is considered advanced and only those who understand physical disk consistency, provisioning, and optimal physical
disk configurations should use this method.
Keep these guidelines in mind when you name a consistency group:
• There is a minimum required capacity for a consistency group repository (depending on your configuration).
• When you define the capacity requirements for a repository, keep in mind any future requirements that you might have for other
virtual disks in this disk group or disk pool. Make sure that you have enough capacity to meet your data storage needs, but you do not
over allocate because you can quickly use up all the storage in your storage array.
• The list of repository candidates can contain both new and existing repository virtual disks. Existing repository virtual disks are left on
the storage array by default when you delete a consistency group. Existing repository virtual disks are placed at the top of the list. The
benefit to reusing an existing repository virtual disk is that you can avoid the initialization process that occurs when you create a new
one.
To create a consistency group repository:
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. Select Manual and click Next to customize the repository candidate settings for the consistency group.
The Consistency Group Repository Settings - Manual window is displayed.
4. Select how you want to filter the repository candidates for each member virtual disk in the consistency group, based on either a
percentage of the base virtual disk capacity or by preferred capacity.
The best repository candidate for each member virtual disk based on the selections you made is displayed.
5. Select Edit individual repository candidates if you want to edit repository candidates for the member virtual disks.
6. Select the repository, from the Repository candidates table, that you want to use for each member virtual disk in the consistency
group.
NOTE: Select a repository candidate that is closest to the capacity you specified.
• The Repository candidates table shows both new and existing repositories that are capable of being used for each member
virtual disk in the consistency group based on the value you specified for percentage or the value you specified for preferred
capacity.
• By default, the system displays the repositories for each member virtual disk of the consistency group using a value of 20% of the
member virtual disk’s capacity. It filters out undersized repository candidates, and those with different Data Service (DS)
attributes. If appropriate candidates are not returned using these settings, you can click Run Auto-Choose to provide automatic
candidate recommendations.
• The Difference column shows the mathematical difference between your selected capacity and the actual capacity of the
repository candidate. If the repository candidate is new, the system uses the exact capacity size that you specified and displays
zero (0) in the Difference column.
Premium feature—Snapshot Virtual Disk
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