Home > Storage > PowerMax and VMAX > Data Protection > Dell EMC PowerMax and VMAX All Flash: Snapshot Policies > Introduction to associating snapshot policies with SGs
There are multiple methods for associating snapshot policies with SGs. Each of the workflows described in this section requires the snapshot policy to be created. Other than the Provisioning Wizard process in Provision Storage wizard, the workflows also require the SG to be created.
You can assign up to four policies to each SG. There is no limit to the number of SGs that can be assigned to a single policy.
The child SGs inherit the policies assigned to a parent SG. When a policy is assigned to a parent SG, the policy takes a snapshot at the parent-SG level and the snapshot is consistent across all child SGs. Conversely, if the policy is individually assigned to each child SG, the child SGs are snapped separately, and the snapshots are not consistent across all child SGs.
SGs that contain common volumes should not be assigned to the same policy because only one SG will be snapped.
CKD SGs can be assigned to snapshot policies. For CKD volumes on z Systems, the best practice is to protect the volumes with either zDP or snapshot policies, but not both.