Patent ID: 7475169

Claim:
A storage control system of a storage system, which comprises said storage control system, and an external storage subsystem, which is a storage subsystem that exists externally of said storage control system, said storage control system comprising: one or more objects to which a plurality of external storage devices is respectively mapped, wherein the plurality of external storage devices are a plurality of storage devices provided in said external subsystem; a memory that stores data either written to an external storage device or read from an external storage device, and which has two or more memory areas respectively allocated to elements of two or more communication paths connecting said storage control system and said plurality of external storage devices; an I/O processor, which receives a first I/O command for a certain object of said one or more objects, and makes an attempt either to acquire data in accordance with the first I/O command, or to secure a storage area for the data in a memory area corresponding to an element of a communication path to the external storage device mapped to said certain object, wherein if said attempt succeeds, said I/O processor sends a processing result of said first I/O command, to a transmission source of the first I/O command, and wherein if said attempt fails, said I/O processor sends a second I/O command for carrying out access in accordance with said first I/O command to the external storage subsystem having said external storage device mapped to said certain object, and thereafter, sends the processing result to said transmission source; a monitor that monitors respective communication states of said two or more communication paths, wherein the communication states relates to one or more measured values of said two or more communication paths, respectively; and an allocating portion that allocates more memory area capacity to an element of a communication path having a poor communication state according to a result of monitoring the communication states, wherein a poor communication state indicates that the one or more measured values of said two or more communication paths, respectively, are greater than a predetermined value.