Release Notes

51 Dell Virtual Storage Manager: Installation Considerations and Local Data Protection | 2079-BP-V-VSM
• Cause no performance impact
• Offer application consistency
• Allow snapshots to be kept indefinitely
Note: A virtual machine can span a VMFS datastore and a vVol datastore, however, this configuration is not
supported for snapshots.
7.2 Protection with VMware vVol snapshots
The workflow for creating a snapshot of a virtual machine stored on a vVol datastore is the same as when it is stored on
a VMFS datastore. However, the snapshot creation method has changed:
1. A snapshot is initiated from vSphere
2. vSphere will optionally quiesce the guest filesystem, requiring VMware Tools to be installed within the virtual
machine.
3. At this point, things diverge from the previous method:
a. vSphere communicates with the PS Series array using the VASA Provider, prepares for snapshot, and takes
snapshot API calls to the array
b. The PS Series array creates a volume snapshot of each data virtual volume (also referred to as a VMDK
virtual volume) in the virtual machine. These volume snapshots use the same technology that has
previously been used for snapshotting traditional volumes.
c. If the option to snapshot the virtual machine memory was selected, vSphere will request an additional
memory virtual volume, where it will write the contents of the virtual machine RAM.
With VMware virtual volume snapshots off-loaded to the PS Series array, the creation and restoration of snapshots is
almost instantaneous. As an array-based snapshot, they can be kept indefinitely, as long as sufficient space is available,
and the VMware limit of the number of snapshots in a chain limit of 32 has not been exceeded.