Remote copy system

• US 20050125465A1
• Filed: 03/10/2004
• Published: 06/09/2005
• Est. Priority Date: 12/03/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ninose, Kenta, Arakawa, Hiroshi, Hirakawa, Yusuke, Asaka, Yoshihiro
• Granted Patent: US 7,085,788 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• 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 11/2082 Data synchronisation
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency ensuring consistency in mirrored systems G06F11/2064
• CPC Class Codes: G06F 2201/835 Timestamp
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

In a system in which data employed by a computer is stored in a storage system, the storage system transfers this data to another storage system and a copy of the data is maintained in the other storage system, consistency of the copy is maintained even in the case of data written to the storage system by a computer, to which a write time is not applied. A source storage system, when a write time is applied to a write request, records the write time and applies this write time to the received write data and, when no write time is applied, applies the recorded write time to the received write data and transfers the write data with this write time applied thereto, to another storage system. The target storage system stores the write data in a logical volume in the target storage system in accordance with the write time.

Claims

1. A system for copying data between a plurality of storage systems, comprising:

a first storage system coupled to a plurality of computers, which comprises a first logical volume storing data received from the plurality of computers; and

a second storage system coupled to said first storage system, which comprises a second logical volume storing copy data of data stored in said first logical volume;

wherein said first storage system assigns time information to write data received from the plurality of computers and sends the write data and the time information to said second storage system; and

said second storage system stores the write data received from said first storage system in said second logical volume in an order based on the time information assigned to the write data.

2. The system according to claim 1, wherein

said first storage system, when a write time is assigned to a write request or the write data received from the plurality of computers, records the received write time and sends the write data with the received write time to said second storage system, and

when a write time has not been applied to the write request or the write data received from the computers, assigns the write time recorded by said first storage system to the received write data and sends the write data with the assigned write time to said second storage system.

3. The system according to claim 2, wherein

said first storage system comprises a plurality of first logical volumes,

said second storage system comprises a plurality of second logical volumes,

each of said plurality of second logical volumes belongs to one of a plurality of logical volume groups, and

said second storage system, in respect of each of said plurality of logical volume groups, records a latest write time in the write times assigned to the write data stored in a logical volume in the logical volume groups and stores the write data, to which a write time indicting time prior to the latest write time has been assigned, in said second logical volume.

4. The system according to claim 3, wherein

said first storage system further assigns a sequential number to the write data for each of the logical volume groups and sends the write data with the assigned sequential number to said second storage system, and

said second storage system stores the write data in the second logical volume in the order of the sequential numbers assigned to the write data for each of the logical volume groups.

5. The system according to claim 4, wherein

said second storage system stores the write data in the sequential number order, so that there is no skipping of the sequential numbers that are assigned to the write data stored in the second logical volume, for each logical volume group.

6. The system according to claim 1, wherein

the time information that is assigned to the write data by said first storage system is a sequential number applied to the write data in the order of reception of the write data.

7. A system for copying data between a plurality of storage systems, comprising:

a first storage system coupled to a plurality of computers, which comprises a first logical volume storing data received from said plurality of computers;

a second storage system comprising a second logical volume, which stores copy data of the data stored in said first logical volume; and

a third storage system comprising a third logical volume, which stores the copy data of the data stored in said first logical volume;

wherein said first storage system stores write data received from said plurality of computers in said first logical volume and sends the write data received from said plurality of computers to said second storage system,

said second storage system assigns time information to the write data received from said first storage system and sends the write data with the time information to said third storage system; and

said third storage system stores the write data received from said second storage system in said third logical volume in accordance with the time information assigned to the write data.

8. The system according to claim 7, wherein

the time information assigned to the write data is a sequential number assigned to the write data in the order of reception of the write data.

9. The system according to claim 7, wherein

said first storage system sends a completion report to at least one computer after receiving a report of reception of the write data from said second storage system.

10. The system according to claim 7, wherein

said first storage system, when a write time is assigned to a write request or the write data received from the plurality of computers, records the received write time and sends the write data with the write time to said second storage system, and

when a write time is assigned to the write data received from said first storage system, said second storage system records the received write time and sends the write data with the write time to the third storage system,

when a write time has not been assigned to the write data received from said first storage system, said second storage system assigns the write time recorded in said second storage system to the received write data and sends the write data with the write time to said third storage system, and

said third storage system stores the received write data in said third logical volume in accordance with the write time assigned to the write data.

11. The system according to claim 10, wherein

said second storage system comprises a plurality of second logical volumes,

said third storage system comprises a plurality of third logical volumes,

said plurality of second logical volumes and said plurality of third of logical volumes respectively belong to one of a plurality of logical volume groups,

said third storage system, in respect of each of said plurality of logical volume groups, records the write time that is closest to the current time in the write times assigned to the write data stored in a logical volume in the logical volume group, and

stores write data, to which a write time indicating time prior to the recorded write time has been assigned, in said third logical volume.

12. The system according to claim 11, wherein

said second storage system further assigns a sequential number to the write data in respect of a logical volume belonging to a logical volume group for each of the logical volume groups and sends the write data with the sequential number to said third storage system, and

said third storage system stores the write data in a third logical volume in the order of the sequential numbers assigned to the write data.

13-20. -20. (canceled)