Selective mirroring in caches for logical volumes

摘要

Methods and structure for selective cache mirroring. One embodiment includes a control unit and a memory. The memory is able to store indexing information for a multi-device cache for a logical volume. The control unit is able to receive an Input/Output (I/O) request from a host directed to a Logical Block Address (LBA) of the logical volume, to consult the indexing information to identify a cache line for storing the I/O request, and to store the I/O request at the cache line on a first device of the cache. The control unit is further able to mirror the I/O request to another device of the cache if the I/O request is a write request, and to complete the I/O request without mirroring the I/O request to another device of the cache if the I/O request is a read request.

主权项

1. A system comprising:
a memory operable to store indexing information for a multi-device cache for a logical volume; and a control unit operable to receive an Input/Output (I/O) request from a host directed to a Logical Block Address (LBA) of the logical volume, to consult the indexing information to identify a cache line for storing data associated with the I/O request, and to store the data at the cache line on a first device of the cache, wherein the control unit is further operable to mirror the data to another device of the cache if the I/O request is a write request, and to complete the I/O request without mirroring the data to another device of the cache if the I/O request is a read request, wherein the control unit is further operable to consult the indexing information to select a candidate cache line, to determine that the candidate cache line is unavailable, and to identify a number of subsequent cache lines to check for availability.