Systems and methods for recovering virtual machines after disaster scenarios

A system for recovering virtual machines after disaster scenarios, the system comprising:

• an identification module programmed to identify a request to restore a virtual machine disk backup image to a virtual machine disk;
• a mapping module programmed to, in response to the request:
• mount a snapshot corresponding to the virtual machine disk backup image;
• after mounting the snapshot, retrieve metadata from a virtual machine mapping service;
• identify, based on the metadata retrieved from the virtual machine mapping service, a block map of the virtual machine disk backup image;
• check the block map to determine whether at least one first block is allocated on the virtual machine disk;
• check the block map to determine whether at least one second block is not allocated on the virtual machine disk;
• check the block map to determine whether the second block is allocated but unused on the virtual machine disk;
• a restoration module programmed to restore the first block from the virtual machine disk backup image to the virtual machine disk upon determining that the block map identifies the first block as allocated, but skip restoration of the second block from the virtual machine disk backup image to the virtual machine disk due to determining that the block map identifies the second block as one of (i) not allocated and (ii) allocated but unused;
• at least one processor configured to execute the identification module, the mapping module, and the restoration module.

A non-transitory computer-readable-storage medium comprising one or more computer-executable instructions that, when executed by at least one processor of a computing device, cause the computing device to:

• identify a request to restore a virtual machine disk backup image to a virtual machine disk;
• in response to the request:
• mount a snapshot corresponding to the virtual machine disk backup image;
• after mounting the snapshot, retrieve metadata from a virtual machine mapping service;
• identify, based on the metadata retrieved from the virtual machine mapping service, a block map of the virtual machine disk backup image;
• check the block map to determine whether at least one first block is allocated on the virtual machine disk;
• check the block map to determine whether at least one second block is not allocated on the virtual machine disk;
• check the block map to determine whether the second block is allocated but unused on the virtual machine disk;
• restore the first block from the virtual machine disk backup image to the virtual machine disk upon determining that the block map identifies the first block as allocated, but skip restoration of the second block from the virtual machine disk backup image to the virtual machine disk due to determining that the block map identifies the second block as one of (i) not allocated and (ii) allocated but unused.