Differential snapshot without array support

A non-transitory processor-readable storage medium having stored therein program code of one or more software programs, wherein the program code when executed by at least one processing device causes the at least one processing device:

• to determine whether one or more of a plurality of data blocks in a first snapshot of a storage volume have changed relative to a plurality of data blocks in a second snapshot of the storage volume, wherein the determining comprises:
• computing a first set of hash values based on the plurality of data blocks in the first snapshot;
• and comparing the first set of hash values to a second set of hash values previously computed based on the plurality of data blocks in the second snapshot, wherein the second set of hash values is stored in an output file that is generated by a first storage system when transmitting data structures corresponding to at least some of the plurality of data blocks in the second snapshot to a remote storage system;
• to generate a respective further data structure for each of the plurality of data blocks in the first snapshot, wherein each of the further data structures comprises a data array field, and wherein the data array field comprises data content of the corresponding data block of the first snapshot only if the corresponding data block has changed relative to the second snapshot;
• and
• to transmit the further data structures to the remote storage system, wherein the remote storage system generates a copy of the first snapshot based at least in part on the further data structures.

An apparatus comprising:

• at least one processing device comprising a processor coupled to a memory;
• the at least one processing device being configured:
• to determine whether one or more of a plurality of data blocks in a first snapshot of a storage volume have changed relative to a plurality of data blocks in a second snapshot of the storage volume, wherein the determining comprises:
• computing a first set of hash values based on the plurality of data blocks in the first snapshot;
• and comparing the first set of hash values to a second set of hash values previously computed based on the plurality of data blocks in the second snapshot, wherein the second set of hash values is stored in an output file that is generated by a first storage system when transmitting data structures corresponding to at least some of the plurality of data blocks in the second snapshot to a remote storage system;
• to generate a respective further data structure for each of the plurality of data blocks in the first snapshot, wherein each of the further data structures comprises a data array field, and wherein the data array field comprises data content of the corresponding data block of the first snapshot only if the corresponding data block has changed relative to the second snapshot;
• and
• to transmit the further data structures to the remote storage system, wherein the remote storage system generates a copy of the first snapshot based at least in part on the further data structures.