Abstract: Methods and apparatus are provided for consistency group replication with reduced resource consumption. An exemplary method comprises: obtaining, by one or more first replication appliances at a first location, one of (i) data generated by a monitored application; and (ii) metadata for each write operation generated by the monitored application, wherein a splitter function provides the data or metadata to the one or more first replication appliances based on a dynamic determination of whether the monitored application requires replication based on the data or the metadata based on predefined application consistency group type criteria; obtaining, by one or more of the first replication appliances, a snapshot comprising the data associated with each of the write operations since a prior snapshot based on the one of the data and the corresponding metadata; and providing the snapshot to one or more second replication appliances at a different location for storage in a replication journal.

Abstract: A changed block bitmap of a volume of storage is represented by a data marker that includes an offset to a first dirty block and an offset to a last dirty block. The blocks between the first and last dirty blocks are represented by contiguous clean block identifiers, contiguous dirty block identifiers, and contiguous mixed clean and dirty block identifiers. The contiguous clean block identifiers and contiguous dirty block identifiers use one or two bits to indicate identifier type. The remaining bits indicate a numerical count of contiguous clean or dirty blocks. The contiguous mixed clean and dirty block identifiers may use one bit per block to indicate change status. The data marker may be smaller than a corresponding changed block bitmap.