US Patent 9015121 Unified virtual machine and data storage snapshots

The system described herein provides for unifying the streams of I/O, external VM snapshot triggers and VM internal operations into one in connection with providing for snapshotting of both the data storage of a storage system and one or more associated VMs over time. The system described herein thereby allows recording undo and redo journals for all the streams substantially simultaneously. The system described herein unifies snapshots for data storage and all associated VMs in response to one or more triggers. A tag of the unified snapshots may therefore automatically refer to a point-in-time of both the VM and array data.