Storage controller

• US 20040199737A1
• Filed: 04/26/2004
• Published: 10/07/2004
• Est. Priority Date: 09/12/1997
• Status: Active Grant

• Current Assignee: Akira Yamamoto, Katsunori Nakamura, Shigeru Kishiro
• Original Assignee: Akira Yamamoto, Katsunori Nakamura, Shigeru Kishiro
• Inventors: Yamamoto, Akira, Kishiro, Shigeru, Nakamura, Katsunori
• Granted Patent: US 7,191,303 B2
• Time in Patent Office: Days
• US Class Current: 711/167
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2074 Asynchronous techniques
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064

Abstract

A primary controller operates to transmit write data and a write time to a secondary controller in the earlier sequence of the write times after reporting a completion of a request for write to a processing unit. The secondary controller stores the write data and the write time transmitted from the primary controller in the cache memory. At a time, the secondary controller stores the write data in a disk unit in the earlier sequence of the write time. These operations make it possible to guarantee all the write data on or before the reference time.

Claims

1. A system for storing data comprising:

a plurality of first storage systems each of which includes a first controller and a first disk unit,

a second storage system including a second cache memory, a second controller, and a second disk unit, and

a third controller coupled to said second storage system,

wherein each of said plurality of first storage systems receives a write data and a write time from a processing unit, and transmits received write data and write time to said second storage system, and

wherein said second controller stores a plurality of write data received from said plurality of first storage systems to said second cache memory, receives a destageable time from said third controller, and stores a write data from said second cache memory to said second disk unit if a write time corresponding to said write data is earlier than said destageable time.

2. The system of claim 1, wherein said third controller receives a plurality of first reference times from said plurality of first storage systems, and determines said destageable time based on said plurality of first reference times.

3. The system of claim 1, further comprising:

a plurality of second storage systems, and

wherein each of said plurality of second storage systems receives a plurality of first reference times from said plurality of first storage systems, determines a second reference time based on the received plurality of first reference times, and transmits said second reference time to said third controller, and

wherein said third controller determines said destageable time based on a plurality of second reference times received from said plurality of second storage systems.

4. The system of claim 3, wherein said second reference time is an earliest time in said plurality of first reference times received from said plurality of first storage systems, and said destageable time is an earliest time in said plurality of second reference times received from said plurality of second storage systems.

5. A storage system coupled to a plurality of other storage systems comprising:

a disk controller coupled to said plurality of other storage systems;

a disk unit coupled to said disk controller; and

a cache memory;

wherein said disk controller receives plural pairs of write data and write time from said plurality of other storage systems, stores a write data to said cache memory, receives a destageable time from a controller coupled to said disk controller, and stores a write data from said cache memory to said disk unit if a write time corresponding to said write data is earlier than said destageable time.

6. The storage system of claim 5, wherein said destageable time is determined by said controller based on a plurality of first reference times received from said plurality of other storage systems.

7. The storage system of claim 5, further comprising:

a plurality of disk controllers, and

wherein each of said plurality of disk controllers receives a plurality of first reference times from said plurality of other storage systems, determines a second reference time based on the received plurality of first reference times, and transmits said second reference time to said controller, and

wherein said destageable time is determined by said controller based on a plurality of second reference times received from said plurality of disk controllers.

8. The system of claim 7, wherein said second reference time is an earliest time in said plurality of first reference times, and said destageable time is an earliest time in said plurality of second reference times.

9. The system for storing data comprising:

a plurality of first storage systems each of which includes a first controller and a first disk unit, and

a plurality of second storage systems each of which includes a second cache memory, a second controllers, and a second disk unit,

wherein each of said plurality of first storage systems receives a write data and a write time from a processing unit, and transmits received write data and write time to a second storage system, and

wherein each of plurality of second controller stores a plurality of write data received from a first storage system to a second cache memory, receives a destageable time determined based on a write time of a write data to be transmitted to a second storage system, and stores a write data from said second cache memory to a second disk unit if a write time corresponding to said write data is earlier than said destageable time.

10. The system of claim 9, wherein said destageable time is an earliest write time of write data to be transmitted to a second storage system.

11. The storage system coupled to a plurality of other storage systems comprising:

a disk controller coupled to said plurality of other storage systems;

a disk unit coupled to said disk controller; and

a cache memory;

wherein said disk controller receives plural pairs of write data and write time from said plurality of other storage systems, stores a write data to said cache memory, receives a destageable time, and stores a write data from said cache memory to said disk unit if a write time corresponding to said write data is earlier than said destageable time.

12. The storage system of claim 11, wherein said destageable time is determined according to a write time of a write data to be sent from one of said plurality of other storage systems.

13. The storage system of claim 12, wherein said destageable time is an earliest write time of write data to be sent from one of said plurality of other storage systems.

14. A system for storing data comprising:

a first storage system coupled to a processing unit, said first storage system comprises first disk units, a first controller, and a first cache memory; and

a second storage system coupled to said first storage system, said second storage system comprises second disk units, a second controller, and a second cache memory,

wherein said first controller receives write data from said processing unit, stores the received write data in said first cache memory, reports completion of writing to said processing unit, and after reporting the completion of writing, transmits the received write data and reference information to said second controller, and

wherein said second controller stores the received write data to said second cache memory, and according to the received reference information, selects write data, which can be stored in a second disk unit, from write data being stored in said second cache memory.

15. A system according to claim 14, wherein said second controller stores the selected write data in a second disk unit, and

wherein when failure takes place to said first storage system, said second controller scraps write data in said second cache memory, without storing said write data in a second disk unit, according to the received reference information.

16. A system according to claim 14, wherein said first controller transmits the received write data and write time of the write data to said second controller, and

wherein said second controller reports the completion of writing to said first controller after storing the received write data in said second cache memory, and after reporting the completion of writing, selects write data, which can be stored in a second disk unit, from write data being stored in said second cache memory according to the write time of the write data.