Method and apparatus for cooperative distributed task management in a storage subsystem with multiple controllers using cache locking

#This application is related to the following co-pending and commonly-assigned U.S. patent application, which is hereby incorporated herein by reference in their respective entirety:

#“METHOD AND APPARATUS FOR USING CACHE COHERENCY LOCKING TO FACILITATE ON-LINE VOLUME EXPANSION IN A MULTI-CONTROLLER STORAGE SYSTEM” to McKean et al., having U.S. patent application Ser. No. 10/084,404.

#1. Field of the Invention

#Referring now to the drawings in which like reference numbers represent corresponding parts throughout:

#FIG. 1 illustrates a block diagram of a typical RAID storage subsystem, having multiple active disk array controllers, in which the methods and associated apparatus of the present invention may be applied;

#FIG. 2 illustrates a flow chart of the method for cooperative distributed task management in a storage subsystem with multiple controllers using cache locking according to the present invention;

#In the following description of the exemplary embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration the specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention.

#The present invention provides a method and apparatus for cooperative distributed task management in a storage subsystem with multiple controllers using cache locking. The present invention distributes a task across a set of controllers acting in a cooperative rather than a master/slave nature to perform discrete components of the subject task on an as-available basis. This minimizes the amount of time required to perform incidental data manipulation tasks, thus reducing the duration of instances of degraded system performance.

#FIG. 1 illustrates a block diagram of a typical RAID storage subsystem 100, having multiple active disk array controllers 118 and 120, in which the methods and associated apparatus of the present invention may be applied. RAID storage subsystem 100 includes at least one pair of multiple active disk array controllers 118 and 120 that are in turn connected to disk array 108 via bus (or busses) 150 and to host computer 102 via bus 154. Disk array 108 is comprised of a plurality of disk drives 110. One of ordinary skill in the art will readily recognize that interface bus 150 between the multiple active disk array controllers 118 and 120 and disk array 108 (including disk drives 110) may be any of several industry standard interface busses including SCSI, IDE, EIDE, IPI, Fiber Channel, SSA, PCI, etc. Circuits (not shown) within multiple active disk array controllers 118 and 120 appropriate to controlling bus 150 are well known to those of ordinary skill in the art. Interface bus 154 between multiple active disk array controllers 118 and 120 and host computer 102 may be any of several standard industry interface busses including SCSI, Ethernet (LAN), Token Ring (LAN), etc. Circuits (not shown) within multiple active disk array controllers 118 and 120 appropriate to controlling bus 154 are well known to those of ordinary skill in the art.