Patent ID: 8484416

Claim:
A method for active-active RAID (Redundant Array of Independent Disks) functionality for a DAS (Direct Attached Storage) RAID system using storage controllers connected in a SAS (Serial Attached SCSI (Small Computer System Interface)) architecture comprising: connecting a plurality of storage controllers to an expander system, said expander system supporting SAS zoning; connecting a plurality of physical storage devices (PDs) to said expander system; configuring zoning of said DAS RAID system such that there is a plurality of separate and unique PD subset zones, each PD subset zone of said plurality of PD subset zones is zoned in with one storage controller of said plurality of storage controllers, each PD subset zone is further zoned in with a unique subset of PDs from said plurality of PDs, and each unique subset of PDs does not have cross-membership of PDs with another subset of PDs zoned in with a different PD subset zone, such that each PD subset zone of said plurality of subset zones is zoned in with said one storage controller of said plurality of storage controllers and not a host server associated with said one storage controller of said plurality of storage controllers permitting said host server associated with said one storage controller to also be associated with other storage controllers of said plurality of storage controllers and other PD subset zones of said plurality of subset zones without affecting zoning restrictions and function of said one storage controller of said plurality of storage controllers; detecting by at least one functioning storage controller of said plurality of storage controllers that another storage controller has failed; reconfiguring by said at least one functioning storage controller of said plurality of storage controllers said zoning of said DAS RAID system such that each PD from said unique subset of PDs zoned in with said separate and unique PD subset zone that corresponds to said failed another storage controller is zoned in with said separate and unique PD subset zone that corresponds to one of said plurality of storage controllers that have not failed, and each PD of said PDs from said unique subset of PDs zoned in with said separate and unique PD subset zone that corresponds to said failed another storage controller is zoned out of said separate and unique PD subset zone that corresponds to said failed another storage controller; and accessing PDs from each unique subset of PDs of said plurality of unique subsets of PDs by said storage controller that is zoned in with each separate and unique PD subset zone that corresponds to each unique subset of PDs of said plurality of unique subsets of PDs as reconfigured to zone out said failed another storage controller.