Abstract: In a data storage system in which a first storage array and a second storage array maintain first and second replicas of a production volume, the first storage array is responsive to a write command from a host to send a notification to the second storage array indicating that the replicated production volume will be updated. The notification has information that enables the second storage array to implement pre-processing steps to prepare for subsequent receipt of data associated with the write command. Both storage arrays implement the pre-processing steps at least partly concurrently. When the data associated with the write command is subsequently received, the first storage array writes the data to cache and then sends a copy of the data to the second storage array, i.e. in series. The second storage array then writes the data to cache. Elapsed time between receipt of the write command and returning an acknowledgment to the host may be improved by concurrent pre-processing.

Abstract: Architectures and techniques are described that can address challenges associated with engaging a procedure that has the potential to produce beneficial effects in some case and detrimental effects in other cases. One example can be engaging an early IO (EIO) protocol in a synchronous remote data facility (SRDF), but only when doing so will have a positive impact on performance and/or response times.

Abstract: Architectures and techniques are described that can address challenges associated with engaging a procedure that has the potential to produce beneficial effects in some case and detrimental effects in other cases. One example can be engaging an early IO (EIO) protocol in a synchronous remote data facility (SRDF), but only when doing so will have a positive impact on performance and/or response times.

Abstract: In a data storage system in which a first storage array and a second storage array maintain first and second replicas of a production volume, the first storage array is responsive to a write command from a host to send a notification to the second storage array indicating that the replicated production volume will be updated. The notification has information that enables the second storage array to implement pre-processing steps to prepare for subsequent receipt of data associated with the write command. Both storage arrays implement the pre-processing steps at least partly concurrently. When the data associated with the write command is subsequently received, the first storage array writes the data to cache and then sends a copy of the data to the second storage array, i.e. in series. The second storage array then writes the data to cache. Elapsed time between receipt of the write command and returning an acknowledgment to the host may be improved by concurrent pre-processing.

Abstract: Techniques for processing I/O operations may include: receiving, at a first data storage system from a host, a write operation that writes data to a logical device; sending the write operation in a synchronous manner to a plurality of other data storage systems, wherein the first data storage system and the plurality of other data storage systems form a linear chain over which the write operation is transmitted; and sending an acknowledgement to the host regarding completion of the write operation only after the first data storage system and each of the plurality of other data storage systems have acknowledged completion of the write operation.