Disk drive array memory system using nonuniform disk drives

• US 5,430,855 A
• Filed: 08/31/1994
• Issued: 07/04/1995
• Est. Priority Date: 02/06/1991
• Status: Expired due to Term

• Current Assignee: Storage Technology Corp (Oracle Corporation)
• Original Assignee: Storage Technology Corp (Oracle Corporation)
• Inventors: Walsh, Robert, Rudeseal, George A., Belsan, Jay S.
• Primary Examiner(s): Bowler, Alyssa H.
• Assistant Examiner(s): DONAGHUE, LARRY D
• Application Number:
  US08/299,247
• Time in Patent Office: 307 Days
• Field of Search: 395/575, 395/800, 395/500, 395/400, 395/425, 371/10.1, 371/10.2, 360/73.02, 360/73.03
• US Class Current: 710/10
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• CPC Class Codes: G11C 29/70 Masking faults in memories by using spares or by reconfiguring
• CPC Class Codes: G11C 29/74 using duplex memories, i.e. using dual copies

Abstract

The data storage subsystem is implemented using an array of data storage elements which vary in data storage characteristics and/or data storage capacity. Control apparatus automatically compensates for any nonuniformity among the data storage elements by selecting a set of physical characteristics that define a common data storage element format. The selected set of physical characteristics may not match any of the disk drives but each disk drive can emulate these selected characteristics. This capability enables the disk drives in the data storage subsystem to be replaced by nonidentical disk drives in a nondisruptive manner to provide continuous data availability.

Claims

1. A data storage system, having a plurality of disk drives each having a single set of at least two predefined data storage characteristics, for storing data records for at least one associated data processor, comprising:

a controller, responsive to one of said disk drives having at least one of said at least two data storage characteristics different than a corresponding one of said at least two data storage characteristics of the remaining ones of said plurality of disk drives, for selecting a common disk drive format comprising a set of said data storage characteristics that are emulatable by all of said plurality of disk drives, comprising;

means for selecting at least one of said data storage characteristics,

means for querying each said disk drive to determine a disk drive format, corresponding to said selected data storage characteristics, implemented on each of said disk drives,

means for selecting a disk drive format, corresponding to said selected data storage characteristic, that is emulatable by each of said disk drives;

means for configuring said plurality of disk drives to match said selected common disk drive format; and

means, responsive to the receipt of a stream of data records from said associated data processor, for writing said received stream of data records in available memory space in one of said disk drives.

2. The system of claim 1 further comprising:

means for querying all said disk drives to determine said data storage characteristics of each of said disk drives.

3. The system of claim 1 wherein said selecting means includes:

means for generating a template indicative of data storage characteristics commonly emulatable by said plurality of disk drives.

4. The system of claim 3 wherein said configuring means includes:

means for storing data indicative of the mapping of the physical tracks of each of said disk drives to said template.

5. The system of claim 1 further comprising:

means, responsive to the subsequent receipt of modifications to one of said data records stored in one of said disk drives from said associated data processor, for writing said modified data record in available memory space in one of said disk drives; and

means for converting said memory space used to store said originally received data record to available memory space.

6. The system of claim 1 further comprising:

means for reserving at least one of said disk drives as backup disk drives, which backup disk drives are shared in common by the remaining ones of said disk drives;

means for identifying one of said disk drives that fails to function; and

means for switchably connecting one of said backup disk drives in place of said identified failed disk drive.

7. The system of claim 6 wherein said configuring means is responsive to said backup disk drive being switched in place of said identified failed disk drive for configuring said backup disk drive to match the configuration of said identified failed disk drive.

8. The system of claim 1 wherein said selecting means includes:

means for selecting the number of sectors per track in said common disk drive format to match the disk drive in said plurality of disk drives having the lowest number of sectors per track.

9. The system of claim 1 wherein said selecting means includes:

means for selecting the number of tracks per volume in said common disk drive format to match the disk drive in said plurality of disk drives having the lowest number of tracks per volume.

10. The system of claim 1 further including:

means for maintaining data indicative of the correspondence between each said received stream of data records and the identity of the one of said disk drives on which said received stream of data records is stored.

11. The system of claim 10 further including:

means for maintaining data indicative of the correspondence between each said received stream of data records and the identity of the physical location of said data record on said one disk drive on which said received stream of data records is stored.

12. The system of claim 11 further including:

means for maintaining data indicative of the mapping of said common disk drive format to the physical characteristics of said one disk drive.

13. In a data storage system having a plurality of disk drives, each having a single set of at least two predefined data storage characteristics, a method for storing data records for at least one associated data processor comprising the steps of:

selecting, in response to one of said plurality of disk drives having at least one of said at least two data storage characteristics different than a corresponding one of said at least two data storage characteristics of the remaining ones of said plurality of disk drives, a common disk drive format comprising a set of said data storage characteristics that are emulatable by all of said plurality of disk drives, comprising;

selecting at least one of said data storage characteristics,

querying each said disk drive to determine a disk drive format, corresponding to said selected data storage characteristic, implemented on each of said disk drives,

selecting a disk drive format, corresponding to said selected data storage characteristic, that is emulatable by each of said disk drives;

configuring said disk drives to match said common disk drive format; and

writing, in response to the receipt of a stream of data records from said associated data processor, said received stream of data records in available memory space in one of said plurality of disk drives.

14. The method of claim 13 further comprising the step of:

querying all said disk drives to determine the data storage characteristics of each of said disk drives.

15. The method of claim 13 wherein said step of selecting includes:

generating a template indicative of data storage characteristics commonly emulatable by all said plurality of disk drives.

16. The method of claim 15 wherein the step of configuring includes:

storing data indicative of the mapping of the physical tracks of each of said disk drives to said template.

17. The method of claim 13 further comprising the steps of:

writing, in response to the subsequent receipt of modifications to one of said data records stored in said disk drives from said associated data processor, said modified data record in available memory space in one of said disk drives; and

converting said memory space used to store said originally received data record to available memory space.

18. The method of claim 13 further comprising the steps of:

reserving at least one of said plurality of disk drives as backup disk drives, which backup disk drives are shared in common by the remaining ones of said disk drives;

identifying one of said disk drives that fails to function; and

switchably connecting one of said backup disk drives in place of said identified failed disk drive.

19. The method of claim 18 wherein said step of configuring includes configuring, in response to said backup disk drive being switched in place of said identified failed disk drive, said backup disk drive to match the configuring of said failed disk drive.

20. The method of claim 13 wherein the step of selecting includes:

selecting the number of sectors per track in said common disk drive format to match the disk drive in said plurality of disk drives having the lowest number of sectors per track.

21. The method of claim 13 wherein said step of selecting includes:

selecting the number of tracks per volume in said common disk drive format to match the one of said disk drives in said plurality of disk drives that has the lowest number of tracks per volume.

22. The method of claim 13 further including the step of:

maintaining data indicative of the correspondence between each said received stream of data records and the identity of the one of said disk drives on which said received stream of data records is stored.

23. The method of claim 22 further including the step of:

maintaining data indicative of the correspondence between each said received stream of data records and the identity of the physical location of said data record on each of said plurality of disk drives on which said received stream of data records is stored.

24. The method of claim 23 further including the step of:

maintaining data indicative of the mapping of said common disk drive format to the physical characteristics of said one disk drive.

25. A disk memory system for storing data records that are accessible by at least one associated data processor, comprising:

a plurality of disk drives, each having a single set of at least two predefined data storage characteristics, for storing data thereon, a number of said disk drives being configured into at least two redundancy groups, each said redundancy group including n+m of said plurality of disk drives, where n and m are both positive integers with n greater than 1 and m equal to or greater than 1;

a controller, responsive to one of said disk drives in said redundancy group having at least one of said at least two data storage characteristics different than a corresponding one of said at least two data storage characteristics of the remaining disk drives in said redundancy group, for selecting a common disk drive format comprising a set of said data storage characteristics that are emulatable by all said disk drives in said redundancy group, comprising

means for selecting at least one of said data storage characteristics,

means for querying each said disk drive to determine a disk drive format, corresponding to said selected data storage characteristic, implemented on each of said disk drives,

means for selecting a disk drive format, corresponding to said selected data storage characteristic, that is emulatable by each of said disk drives;

means for configuring all said disk drives in said redundancy group to match said common disk drive format;

means for storing each stream of data records received from said associated data processing devices on successive ones of said n disk drives in a selected redundancy group;

means, responsive to said storing means storing streams of data records on all n disk drives in said selected redundancy group, for generating m segments of redundancy information for said data records stored on said n disk drives; and

means for writing said m segments of redundancy information on to said m disk drives of said selected redundancy group.

26. The system of claim 25 further comprising:

means for querying all said disk drives in said redundancy group to determine said data storage characteristics of each of said disk drives.

27. The system of claim 25 wherein said selecting means includes:

means for generating a template indicative of data storage characteristics commonly emulatable by all said disk drives in said redundancy group.

28. The system of claim 27 wherein said configuring means includes:

means for storing data indicative of the mapping of the physical tracks of each disk drive in said redundancy group to said template.

29. The apparatus of claim 25 wherein said system further comprises:

means, responsive to the subsequent receipt of modifications to one of said data records stored in one of said redundancy groups from said associated data processor, for writing said modified data record in available memory space in one of said redundancy groups; and

means for converting said memory space used to store said originally received data record to available memory space.

30. The system of claim 25 further comprising:

means for reserving at least one of said plurality of disk drives as backup disk drives, which backup disk drives are shared in common by said redundancy groups;

means for identifying one of said disk drives in one of said redundancy groups that fails to function; and

means for switchably connecting one of said backup disk drives in place of said identified failed disk drive.

31. The system of claim 30 wherein said configuring means is responsive to said backup disk drive being switched in place of said identified failed disk drive for configuring said backup disk drive to match the configuring of the disk drives in said redundancy group.

32. The system of claim 25 wherein said selecting means includes:

means for selecting the number of sectors per track in said common disk drive format to match the disk drive in said redundancy group having the lowest number of sectors per track.

33. The system of claim 25 wherein said selecting means includes:

means for selecting the number of tracks per volume in said common disk drive format to match the disk drive in said redundancy group having the lowest number of tracks per volume.

34. The system of claim 25 further including:

means for maintaining data indicative of the correspondence between each said received stream of data records and the identity of the one of said disk drives in said selected redundancy group on which said received stream of data records is stored.

35. The system of claim 34 further including:

means for maintaining data indicative of the correspondence between each said received stream of data records and the identity of the physical location of said data record on each of said plurality of disk drives in said selected redundancy group on which said received stream of data records is stored.

36. The system of claim 35 further including:

means for maintaining data indicative of the mapping of said common disk drive format to the physical characteristics of said one disk drive.

37. In a disk memory system having a plurally, of disk drives, each having a single set of at least two predefined data storage characteristics, for storing data thereon, a method of storing data records that are accessible by at least one associated data processor comprising the steps of:

configuring a number of said disk drives into at least two redundancy groups, each said redundancy group including n+m of said plurality of disk drives, where n and m are both positive integers with n greater than 1 and m equal to or greater than 1;

selecting, in response to one of said disk drives in said redundancy group having at least one of said at least two data storage characteristics different than a corresponding one of said at least two data storage characteristics of the remaining disk drives in said redundancy group, a common disk drive format comprising a set of said data storage characteristics that are emulatable by all said disk drives in said redundancy group, comprising;

selecting at least one of said data storage characteristics,

querying each said disk drive to determine a disk drive format, corresponding to said selected data storage characteristic, implemented on each of said disk drives,

selecting a disk drive format, corresponding to said selected data storage characteristic, that it emulatable by each of said disk drives;

configuring all said disk drives in said redundancy group to match said common disk drive format;

storing each stream of data records received from said associated data processing devices on successive ones of said n disk drives in a selected redundancy group;

generating, in response to storing streams of data records on all n disk drives in said selected redundancy group, m segments of redundancy information for said data records stored on said n disk drives; and

writing said m segments of redundancy information on to said m disk drives of said selected redundancy group.

38. The method of claim 37 further comprising the step of:

querying all said disk drives in said redundancy group to determine the data storage characteristics of each of said disk drives.

39. The method of claim 37 wherein said step of selecting includes:

generating a template indicative of data storage characteristics commonly emulatable by all said disk drives in said redundancy group.

40. The method of claim 37 wherein said step of configuring includes:

storing data indicative of the mapping of the physical tracks of each disk drive in said redundancy group to said template.

41. The method of claim 37 further comprising the steps of:

writing, in response to the subsequent receipt of modifications to one of said data records stored in one of said redundancy groups from said associated data processor, said modified data record in available memory space in one of said redundancy groups; and

converting said memory space used to store said originally received data record to available memory space.

42. The method of claim 41 further comprising the steps of:

reserving at least one of said plurality of disk drives as backup disk drives, which backup disk drives are shared in common by said redundancy groups;

identifying one of said disk drives in one of said redundancy groups that fails to function; and

switchably connecting one of said backup disk drives in place of said identified failed disk drive.

43. The method of claim 42 wherein said step of configuring includes configuring, in response to said backup disk drive being switched in place of said identified failed disk drive, said backup disk drive to match the configuring of the disk drives in said redundancy group.

44. The method of claim 37 wherein the step of selecting includes:

selecting the number of sectors per track in said common disk drive format to match the one of said disk drives in said redundancy group having the lowest number of sectors per track.

45. The method of claim 37 wherein said step of selecting includes:

selecting the number of tracks per volume in said common disk drive format to match the one of said disk drives in said redundancy group having the lowest number of tracks per volume.

46. The method of claim 37 further including the step of:

maintaining data indicative of the correspondence between each said received stream of data records and the identity of the one of said disk drives in said selected redundancy group on which said received stream of data records is stored.

47. The method of claim 46 further including the step of:

maintaining data indicative of the correspondence between each said received stream of data records and the identity of the physical location of said data record on each of said plurality of disk drives in said selected redundancy group on which said received stream of data records is stored.

48. The method of claim 37 further including the step of:

maintaining data indicative of the mapping of said common disk drive format to the physical characteristics of said one disk drive.