Dot Hill/Seagate CSSG Assigned Patent

Dot Hill Systems Corporation, (part of Seagate CSSG), Longmont, CO, has been assigned a patent (9,378,145) developed by Viswanatha, Ritvik, Longmont, CO, for a “storage controller cache synchronization method and apparatus.”

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A method for a pair of redundant storage controllers to ensure reliable cached write data transfers to storage device logical volumes is provided. The method includes maintaining metadata including a first number identifying which controller currently owns the volume, a second number identifying which controller previously owned the volume, a third number identifying which controller is a preferred owner of the volume, and an indication if the volume is write protected. The method also includes determining if all volumes currently owned by the controller are write protected. If all volumes currently owned by the controller are write protected, then the method includes verifying that the second controller is working and transferring cache data from the second controller to the first controller. If all volumes currently owned by the first controller are not write protected, then the method includes updating the second number and placing all volumes online.“

The patent application was filed on March 4, 2014 (14/196,470).