Patent ID: 6957301

Claim:
A method for managing storage, said method comprising the steps of: a first storage controller receiving a write command from a host computer to write host data to a disk, and in response, writing said host data into a cache memory in said first storage controller, and before said host data is written from said cache memory to said disk or a portion of said disk, recording on said disk or the disk portion an identity of said first storage controller as a current user of said disk or said disk portion and an indication that said first storage controller is operating in a mode in which it stores data in a cache before writing the data to said disk or said disk portion; subsequently shutting down said first storage controller such said host data in said cache memory is not written to said disk or said disk portion and the record of the identity of said first storage controller and the indication that said storage controller is operating in said mode are not cleared; and a second storage controller subsequently accessing said disk or said disk portion and reading said record to learn that said first storage controller was using said disk or said disk portion and operating in said mode before the shutdown; and wherein in response to said reading step, said second storage controller not using stale data in said disk or disk portion for which said host data is an update, and further comprising the steps of said first storage controller being reactivated and writing said host data from said cache memory to said disk or said disk portion, and then said second storage controller using said host data from said disk or said disk portion.