Home > Storage > PowerStore > Virtualization and Cloud > Dell PowerStore: Virtualization Integration > Protection
The Protection card enables administrators to manage snapshots and configure protection policies for a VM. This page enables you to create a manual snapshot or modify and delete existing snapshots. Before PowerStoreOS 3.0, a protection policy could also be applied to the VM to take snapshots automatically, such as for volumes and file systems. With the release of PowerStoreOS 3.0, snapshot schedules are only applied to a virtual machine through vSphere using VM Storage Policies. See the section Storage Policy Based Management for more details about VM Storage Policies.
The following figure shows the VM protection page where you can configure snapshots and protection policies:
VM snapshots are visible in both PowerStore Manager and vCenter, regardless of where they are created. You can view information about VM snapshots in the Manage Snapshots page in vCenter. You can also initiate a revert operation from here to restore the VM using the snapshot. You can revert to any snapshot in the snapshot tree.
Snapshots that are taken from PowerStore do not include the guest VM memory. This behavior means that the VM memory contents and power state are not preserved, but the snapshot is crash consistent. After the snapshot restore operation completes, the VM reverts to a powered-off state and can be powered back on. The following figure shows a VM with manual and scheduled snapshots that are created from PowerStore:
vSphere enforces a limit of 31 snapshots for each VM. If this limit is reached, the oldest snapshot is automatically deleted chronologically starting with the oldest when the next snapshot is created by the policy. Although manually created snapshots count towards this limit, they are never automatically deleted because they do not have an expiration date.
In large environments, it is possible to initiate many snapshot requests to vCenter at once. To prevent overloading vCenter, PowerStore sends a maximum of five simultaneous create snapshot operations to vCenter. The remaining operations are queued and started as each create snapshot operation completes. PowerStore also sends a maximum of five simultaneous delete snapshot operations to vCenter. Although the create snapshot operations are sent individually, delete snapshot operations can be sent in batches, up to a limit of five. Because these two limits are different, it is possible to have a total of five create and five delete snapshot operations simultaneously on different VMs.
For more information about snapshots and protection policies, see the document PowerStore: Snapshots and Thin Clones.