Dell PowerVault MD3820f - Manual (Page 164)

create the repository automatically using the default settings or you can manually create the repository
by defining the capacity settings for the repository.
You are initially creating an overall repository with one individual repository virtual disk. However, the
overall repository can contain multiple repository virtual disks in the future for expansion purposes.
Use the Consistency Group Snapshot Virtual Disk Repository Settings - Manual option to manually
define the capacity requirements for a consistency group snapshot virtual disk repository. The Manual
method is considered advanced and only those who understand physical disk redundancy, provisioning,
and optimal physical disk configurations should use this method.
The following guidelines apply:
• There is a minimum required capacity for a snapshot virtual disk repository (depending on your
configuration).
• When you define the capacity requirements for a repository, keep in mind any future requirements
that you may 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
snapshot virtual disk. 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 snapshot virtual disk repository:
1. From the AMW, select the Storage & Copy Services tab.
2. Select the consistency group to which you want to add member virtual disks and then select Copy
Services → Consistency Group → Remove Member Virtual Disks.
The Consistency Group Snapshot Virtual Disk Settings window is displayed.
3. Select Manual and click Next to customize the repository candidate settings for the consistency
group.
The Consistency Group Snapshot Virtual Disk Repository Settings - Manual window is displayed.
4. Select how you want 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 your selections 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.
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 percent 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.
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