Patent attributes
Described are techniques executed in a data storage system in connection with processing an I/O request. The I/O request is received. It is determined whether the I/O request is a write request. If the I/O request is a write request, write request processing is performed. The write request processing includes: copying write request data of the write request to cache; destaging the write request data from the cache to a primary storage device; and copying, in accordance with a heuristic, the write request data from the primary storage device to an asynchronous mirror device including an asynchronous copy of data from the primary storage device, wherein the asynchronous mirror device is write disabled with respect to received write requests requesting to write data thereto, the asynchronous mirror device used for servicing data requested in connection with read requests upon the occurrence of a cache miss.
