Patent ID: 7340555
Filing Date: 2008-03-04
Classification: G06F

Abstract:
1. A method for performing a mirrored posted-write operation in a system having first and second redundant array of inexpensive disks (RAID) controllers in communication via a high-speed communications link, each of the RAID controllers having a CPU, a cache memory, and a bus bridge that bridges the CPU, cache memory, and communications link, the cache memory having first and second sets of write cache buffers, and corresponding valid indicators for indicating whether each of the write cache buffers of the second set contains valid data to be flushed to a disk array by the RAID controller if the other RAID controller fails, the method comprising: receiving, by the bus bridge of the first RAID controller, data transmitted to the first RAID controller by a host computer; writing, by the bus bridge of the first RAID controller, the data to one or more of the first set of write cache buffers of the first RAID controller, in response to said bus bridge of the first RAID controller receiving the data transmitted by the host computer; broadcasting, by the bus bridge of the first RAID controller, a copy of the data to the bus bridge of the second RAID controller via the link, in response to said bus bridge of the first RAID controller receiving the data transmitted by the host computer; receiving, by the bus bridge of the second RAID controller, the copy of the data via the communications link; writing, by the bus bridge of the second RAID controller, the copy of the data to one or more of the second set of write cache buffers of the second RAID controller, in response to said receiving the copy of the data; and updating one or more of the corresponding valid indicators of the second RAID controller to indicate that said one or more of the second set of write cache buffers of the second RAID controller does not contain valid data, wherein said updating the valid indicators is performed automatically by the bus bridge of the second RAID controller in response to said receiving the copy of the data, wherein the bus bridge of the second RAID controller automatically performs the updating of the valid indicators prior to said writing the copy of the data, wherein the CPU of the second RAID controller is alleviated from updating the valid indicators because the bus bridge of the second RAID controller automatically updates the valid indicators.