Systems and methods for migrating virtual machines

A system for migrating virtual machines, the system comprising:

• an identification module programmed to:
• identify a request to migrate a virtual machine from a primary site to a secondary site, wherein:
• the primary site comprises a primary storage device used for storage by the virtual machine;
• the primary storage device has been configured for asynchronous replication to a secondary storage device at the secondary site prior to identifying the request to migrate the virtual machine from the primary site to the secondary site;
• identify a difference map that:
• reflects differences between data on the primary storage device and asynchronously replicated data on the secondary storage device;
• provides information for use in determining whether the asynchronously replicated data on the secondary storage device can be leveraged to fulfill input/output attempts from the virtual machine at the secondary site that are intercepted after the virtual machine has been initiated at the secondary site;
• an initiation module programmed to initiate, before the primary storage device has been completely replicated to the secondary storage device, the virtual machine at the secondary site;
• an interception module programmed to intercept at least one input/output attempt from the virtual machine at the secondary site to the secondary storage device;
• a determination module programmed to determine, based on the difference map, that a region indicated in the input/output attempt has not yet been synchronized from the primary storage device;
• a retrieval module programmed to retrieve the region from the primary storage device before allowing the input/output attempt to proceed;
• at least one processor configured to execute the identification module, the initiation module, the interception module, the determination module, and the retrieval 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 migrate a virtual machine from a primary site to a secondary site, wherein:
• the primary site comprises a primary storage device used for storage by the virtual machine;
• the primary storage device has been configured for asynchronous replication to a secondary storage device at the secondary site prior to identifying the request to migrate the virtual machine from the primary site to the secondary site;
• identify a difference map that:
• reflects differences between data on the primary storage device and asynchronously replicated data on the secondary storage device;
• provides information for use in determining whether the asynchronously replicated data on the secondary storage device can be leveraged to fulfill input/output attempts from the virtual machine at the secondary site that are intercepted after the virtual machine has been initiated at the secondary site;
• initiate, before the primary storage device has been completely replicated to the secondary storage device, the virtual machine at the secondary site;
• intercept at least one input/output attempt from the virtual machine at the secondary site to the secondary storage device;
• determine, based on the difference map, that a region indicated in the input/output attempt has not yet been synchronized from the primary storage device;
• retrieve the region from the primary storage device before allowing the input/output attempt to proceed.