Disk subsystem and a method for controlling the disk subsystem
AssigneeHitachi, Ltd.
InventorsTakeki Okamoto, Takao Satoh
Life of this patent
Estimating the term…
Abstract
A plurality of magnetic disks are connected to a disk controller A through a fiber switch A and a fiber switch C. A disk controller B is connected to the plurality of magnetic disks through a fiber switch B and a fiber switch D. Access paths on the side of disk controller A and on the side of disk controller B are each interrupted by using associated fiber switches and a new disk controller is added between the fiber switches.
Claims20
A disk subsystem comprising:
- a plurality of first and second memory devices for storing data;
- first and second disk controllers for controlling said plurality of first and second memory devices;
- a cache memory for temporarily holding data to be stored in said plurality of first and second memory devices;
- a common memory for storing control information having mounting status information and operating status information concerning said first and second disk controllers;
- first and second channel controllers connected to a host computer to control input/output interfaces to/from said host computer;
- a first cache switch connected to said first disk controller, cache memory, common memory and first channel controller;
- a second cache switch connected to said second disk controller, cache memory, common memory and second channel controller;
- a first switch circuit connected to one of said plurality of first memory devices and said first disk controller;
- a third switch circuit connected to one of said plurality of second memory devices and said first switch circuit;
- a second switch circuit connected to said first one of said plurality of memory devices and said second disk controller;
- a fourth switch circuit connected to said second one of said plurality of memory devices and said second switch circuit;
- and
- a third disk controller to be added to said third switch circuit during working of said disk subsystem.
A method for controlling a disk subsystem having a plurality of first and second memory devices, first and second disk controllers for controlling said plurality of first and second memory devices, a cache memory for temporarily holding data to be stored in said plurality of first and second memory devices, a common memory for storing control information, first and second channel controllers connected to a host computer to control input/output interfaces to/from said host computer, a first cache switch connected to said first disk controller, cache memory, common memory, and first channel controller, a second cache switch connected to said second disk controller, cache memory, common memory and second channel controller, a first switch circuit connected to one of said plurality of first memory devices and said first disk controller, a third switch circuit connected to one of said plurality of second memory devices and said first switch circuit, a second switch circuit connected to said one of said plurality of first memory devices and said second disk controller, and a fourth switch circuit connected to said one of said plurality of second memory devices and said second switch circuit, said method comprising the steps of:
- blocking said first disk controller in accordance with said control information;
- changing connection of said first switch circuit and said third switch circuit to connection of said third switch circuit and a third disk controller to be connected to said first cache switch;
- releasing said first disk controller from blocking in accordance with said control information;
- and
- placing said third disk controller in usable condition in accordance with said control information.
Dependencies are inferred from the claim text.