System and method for replicating data

• US 6,643,667 B1
• Filed: 03/17/2000
• Issued: 11/04/2003
• Est. Priority Date: 03/19/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Arai, Kouji, Suzuki, Susumu, Yasukawa, Hironori
• Primary Examiner(s): Coby, Frantz
• Application Number:
  US09/528,416
• Time in Patent Office: 1,327 Days
• Field of Search: 707/1, 707/200, 710/33, 711/112, 711/114, 711/167, 714/6
• US Class Current: 707/640
• CPC Class Codes: G06F 11/2087 with a common controller
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

According to the present invention, techniques for controlling copying of logical volumes within a computer storage system are provided. A representative embodiment includes a plurality of storage devices controlled by a control unit, one or more processors, and a buffer memory for temporarily storing data read from the storage devices within the control unit. The storage devices can be addressed as logical volumes.

Claims

1. A method for creating a copy of data in a system comprising a plurality of storage devices, a control unit operable to control said storage devices, and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said method comprising:

specifying a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;

creating a copy of data in said specified first logical volume into said second logical volume;

said creating a copy further comprising;

copying data from said first logical volume to a first location in said memory;

copying said data from said first location in said memory to a second location in said memory;

copying said data from said second location in said memory to said second logical volume;

wherein said copying said data from said first location in said memory to a second location in said memory is performed by said control unit.

2. The method of claim 1, wherein said copying said data from said first location in said memory to a second location in said memory further comprises:

reading data from said first location in said memory into a location within an address change unit;

exchanging a logical address within said data from an address corresponding to said first logical volume to an address corresponding to said second logical volume; and

writing said data to said second location in said memory.

3. The method of claim 1 further comprising:

if a write request is issued to said first logical volume after creating a copy has commenced,

creating a copy of data in said first logical volume to said second logical volume before said data in said first logical volume is modified by said write request.

4. The method of claim 1 wherein said relationship further comprises:

a pairing of a primary volume and a secondary volume.

5. The method of claim 1 further comprising:

modifying a location identifier defined in each logical volume.

6. The method of claim 1 further comprising:

making said second logical volume accessible after said creating a copy of data in said specified first logical volume into said second logical volume.

7. The method of claim 1 further comprising:

tracking modified data, if a write request is issued to said first logical volume or said second logical volume after the copy processing is completed, and

copying said modified data based upon said tracking, if creating a copy is directed again to the pair in copy completed status.

8. The method of claim 1 further comprising:

deleting said relationship.

9. The method of claim 1 wherein said first logical volume is defined as a primary logical volume, said method further comprising:

defining at least one of a plurality of different logical volumes as secondary logical volumes; and

defining multiple pairs comprising said primary logical volume and one of said plurality of secondary logical volumes.

10. The method of claim 9 wherein data in said secondary logical volumes comprises a series of historical records of said primary volume, said historical records obtained by switching said secondary logical volumes one after another.

11. The method of claim 1 further comprising:

displaying information about said first logical volume and said second logical volume.

26. The method of claim 1, wherein said system comprises at least one of a plurality of processing units operable to access said control unit, and wherein said copying said data from said first location in said memory to a second location in said memory is performed by said control unit substantially independently of said processing units.

27. The method of claim 1, wherein said control unit comprises at least one disk adapter, and wherein said at least one disk adapter performs the step of creating a copy of data in said specified first logical volume into said second logical volume.

28. The method of claim 2, wherein said control unit comprises at least one disk adapter, and wherein said at least one disk adapter comprises said address change unit.

12. A method for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said method comprising:

specifying a relationship between said first logical volume and said second logical volume;

creating a copy of data in said first logical volume into said second logical volume;

said creating a copy further comprising;

copying data from said first logical volume to a first location into a memory;

copying said data from said first location in said memory to a second location in said memory;

copying said data from said second location in said memory to said second logical volume;

wherein said copying said data from said first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit.

13. A method for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said method comprising:

specifying a relationship between said first logical volume and said second logical volume;

copying data read from said first logical volume into a memory located within a control unit and thereupon writing said data to said second logical volume; and

wherein said copying said data from a first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit.

14. A computer system comprising a plurality of storage devices, a control unit operable to control said storage devices, and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said control unit operatively disposed to:

establish a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;

create a copy of data in said specified first logical volume into said second logical volume;

said creating a copy further comprising;

copy data from said first logical volume to a first location in said memory;

copy said data from said first location in said memory to a second location in said memory;

copy said data from said second location in said memory to said second logical volume;

wherein said copy said data from said first location in said memory to a second location in said memory is performed by said control unit.

15. The computing system of claim 14 wherein said copy said data from said first location in said memory to a second location in said memory further comprises:

reading data from said first location in said memory into a location within an address change unit;

exchanging a logical address within said data from an address corresponding to said first logical volume to an address corresponding to said second logical volume; and

writing said data to said second location in said memory.

16. The computing system of claim 14 wherein said buffer further comprises 10 Gigabytes of storage.

17. The computing system of claim 14 wherein said plurality of storage devices further comprises a RAID.

18. The computing system of claim 14 further comprising a display, said display operable to depict information about said storage devices.

19. The computing system of claim 14, wherein said control unit further comprises a data recovery and reconstruct (DRR), said DRR operative to copy said data from said first location in said memory to a second location in said memory;

and thereupon change a volume number associated with said data.

29. The method of claim 14, wherein said system comprises at least one of a plurality of processing units operable to access said control unit, and wherein said copying said data from said first location in said memory to a second location in said memory is performed by said control unit substantially independently of said processing units.

30. The method of claim 14, wherein said control unit comprises at least one disk adapter, and wherein said at least one disk adapter is configured to create said copy of data in said specified first logical volume into said second logical volume.

31. The method of claim 15, wherein said control unit comprises at least one disk adapter, and wherein said at least one disk adapter comprises said address change unit.

20. A computer program product for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said computer program product comprising:

code for specifying a relationship between said first logical volume and said second logical volume;

code for creating a copy of data in said first logical volume into said second logical volume;

said code for creating a copy further comprising;

code for copying data from said first logical volume to a first location into a memory;

code for copying said data from said first location in said memory to a second location in said memory;

code for copying said data from said second location in said memory to said second logical volume;

wherein said copying said data from said first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit; and

a computer readable storage medium for holding the codes.

21. A computer program product for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said computer program product comprising:

code for specifying a relationship between said first logical volume and said second logical volume;

code for copying data read from said first logical volume into a memory located within a control unit and thereupon writing said data to said second logical volume; and

wherein said copying said data from said first location in said memory to a second location in said memory is performed by said control unit substantially independently of a central processing unit; and

a computer readable storage medium for holding the codes.

22. The computer program product of claim 21 further comprising:

code for displaying information about said first logical volume and said second logical volume.

23. A control unit for controlling the copying of information, said control unit operable in a computing system comprising at least one of a plurality of storage devices, said control unit operable to control said storage devices, at least one of a plurality of processing units operable to access said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said control unit comprising a memory operable to temporarily store data read from said storage devices within said control unit, said control unit operatively disposed to:

copy data read from said first logical volume into said memory located within said control unit;

copy said data from said memory to a different location within said memory, changing a volume identifier associated with said data, and thereupon writing said data to said second logical volume; and

wherein said copying said data from a first location in said memory to a second location in said memory is performed by said control unit substantially independently of a central processing unit.

24. A computer system comprising a plurality of storage devices, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, at least one of a plurality of processing units, a cache memory operable to temporarily store data, and a control unit operable to store and retrieve data from said storage devices on behalf of said processing units;

wherein said control unit is further operable to copy data from a first logical volume to a second logical volume according to a relationship established between said first logical volume and said second logical volume;

wherein said control unit copies said data from said first logical volume to a first location in said cache memory;

whereupon a data recovery unit within said control unit is operable to create a copy of said data in said first location in said cache memory to a buffer memory within said data recovery unit, and thereupon to copy said data from said buffer memory within said data recovery unit into a second location in said cache memory; and

thereupon to copy said data from said second location in said cache memory to said second logical volume;

wherein said data comprises a logical address section, said logical address section having a data content that is changed during said copying between said cache memory and said memory.

25. A computer system comprising:

a first means for storing data;

a second means for storing data;

a cache means for temporarily storing data;

a data recovery and reconstruction means for creating a copy of data from said first means for storing data into said cache means, and thereupon to create a copy of said data in said cache means into said second means for storing data,

wherein said data comprises a logical address section, said logical address section having a data content that is changed by said data recovery and reconstruction means from a physical address corresponding to said first means for storing data to a physical address corresponding to said second means for storing data.

32. A method for creating a copy of data in a system comprising a plurality of storage devices, a control unit operable to control said storage devices, said control unit comprising at least one disk adapter and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said method comprising:

specifying a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;

said at least one disk adapter creating a copy of data in said specified first logical volume into said second logical volume;

said creating a copy further comprising;

copying data from said first logical volume to a first location in said memory;

copying said data from said first location in said memory to a second location in said memory;

copying said data from said second location in said memory to said second logical volume.

33. The method of claim 32, wherein said system comprises at least one of a plurality of processing units operable to access said control unit, and wherein said copying said data from said first location in said memory to a second location in said memory is performed by said at least one disk adapter substantially independently of said processing units.

34. The method of claim 32, wherein said disk adapter comprises an address change unit, and wherein said copying said data from said first location in said memory to a second location in said memory further comprises:

reading data from said first location in said memory into a location within said address change unit;

exchanging a logical address within said data from an address corresponding to said first logical volume to an address corresponding to said second logical volume; and

writing said data to said second location in said memory.

35. A computer system comprising a plurality of storage devices, a control unit operable to control said storage devices, said control unit comprising at least one disk adapter and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said at least one disk adapter operatively disposed to:

establish a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;

create a copy of data in said specified first logical volume into said second logical volume;

said creating a copy further comprising;

copy data from said first logical volume to a first location in said memory;

copy said data from said first location in said memory to a second location in said memory;

copy said data from said second location in said memory to said second logical volume.

36. The system of claim 35, comprising wherein said system comprises at least one of a plurality of processing units operable to access said control unit, and wherein said copying said data from said first location in said memory to a second location in said memory is performed by said at least one disk adapter substantially independently of said processing units.

37. The method of claim 35, wherein said disk adapter comprises an address change unit, and wherein said copying said data from said first location in said memory to a second location in said memory further comprises:

reading data from said first location in said memory into a buffer location within said address change unit;

exchanging a logical address within said data from an address corresponding to said first logical volume to an address corresponding to said second logical volume; and

writing said data to said second location in said memory.