Dell PowerVault MD3820f - Manual (Page 146)

Creating A Consistency Group Repository (Manually)
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.
For more information on the filter options, see the online help topics.
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.
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