Redundant dynamically distributed file system

• US 20020156974A1
• Filed: 01/29/2002
• Published: 10/24/2002
• Est. Priority Date: 01/29/2001
• Status: Abandoned Application

• Current Assignee: Braodband Storage LLC, Snap Appliance, Inc. (Silicon Valley Technology Partners LLC)
• Original Assignee: Adaptec Incorporated (Steel Partners Holdings LP)
• Inventors: Schweitzer, James R., Bolstad, Gregory D., Staub, John R., Randall, Jay G., Priester, Wilbur George, Ulrich, Thomas R.
• Application Number:
  US10/060,879
• Publication Number:
  US 20020156974A1
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2035 without idle spare hardware
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• 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 16/10 File systems; File servers
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

A redundant dynamically distributed file system is described. The redundant dynamically distributed file system operates on a computer network and includes a first file server that is operably connected to a network fabric and a second file server that is operably connected to the network fabric. The redundant dynamically distributed file system further includes first file system information loaded on the first file server and second file system information loaded on the second file server. The first file system information and the second file system information are configured to allow a client computer that is operably connected to the network fabric to locate files owned by the first file server and files owned by the second file server without prior knowledge as to which file server owns the files. The first file server is configured to store information sufficient to regenerate the second file system information, and the second file server is configured to store information sufficient to regenerate the first file system information.

Claims

1. A computer network file system, comprising:

a first file server operably connected to a network fabric;

a second file server operably connected to the network fabric;

first file system information loaded on said first file server; and

second file system information loaded on said second file server, said first file system information and said second file system information configured to allow a client computer operably connected to said network fabric to locate files owned by said first file server and files owned by said second file server without prior knowledge as to which file server owns said files, said first file server configured to store information sufficient to regenerate said second file system information, and said second file server configured to store information sufficient to regenerate said first file system information.

2. The computer network file system of claim 1, wherein said first file system information comprises first directory information that describes a directory structure of a portion of the network file system whose directories are stored on said first file server and second directory information that describes a directory structure of a portion of the network file system whose directories are stored on said second file server, said first directory information comprising location information for said second directory information, said location information comprising a server id that identifies said second file server.

3. The computer network file system of claim 2, wherein said first directory information comprises a root directory.

4. The computer network file system of claim 1, further comprising a first intent log created by said first server, said first intent log including information describing intended modifications to said first file system information, said first intent log provided to said second file server.

5. The computer network file system of claim 4, wherein said location information further comprises a disk id that identifies a disk drive attached to a file server corresponding to said server id.

6. The computer network file system of claim 4, wherein said directory information comprises at least one Gnid-string.

7. The computer network file system of claim 6, wherein a one-to-one correspondence exists between said at least one Gnid-string and a directory stored on said first file server.

8. The computer network file system of claim 6, wherein said Gnid-string comprises a collection of gnids.

9. The computer network file system of claim 8, wherein each of said gnids comprises information for locating a specified gnode.

10. The computer network file system of claim 9, wherein said information for locating a specified gnode comprises a pointer to said specified gnode.

11. The computer network file system of claim 9, wherein said specified gnode comprises file attributes for a file corresponding to said gnode.

12. The computer network file system of claim 11, wherein said file attributes include at least one of a file id, a file access time, a file creation time, and a file modification time.

13. The computer network file system of claim 9, wherein said specified gnode comprises information for locating a first gee of a plurality of gees corresponding to said gnode.

14. The computer network file system of claim 13, wherein said plurality of gees comprises gnode gees and data gees.

15. The computer network file system of claim 14, wherein each of said gnode gees comprises information to specify an extent.

16. The computer network file system of claim 14, wherein each of said data gees comprises information to specify a first logical disk block and information to specify a disk that contains said first logical block.

17. The computer network file system of claim 13, wherein said plurality of gees further comprises parity gees.

18. The computer network file system of claim 17, wherein each of said parity gees comprises information regarding location of parity data for one or more preceding data gees in said plurality of gees.

19. The computer network file system of claim 13, wherein a parity group comprises a first set of one or more data gees and an associated parity gee.

20. The computer network file system of claim 19, wherein each data gee identifies a block of data and said parity gee identifies a parity block.

21. The computer network file system of claim 20, wherein each block of data and parity in said parity group is stored on a separate disk drive such that no single disk drive contains data from two blocks said parity group.

22. The computer network file system of claim 19, wherein a size of a first parity group is independent of a size of a second parity group.

23. The computer network file system of claim 1, wherein first directory information is mirrored on said second file server.

24. The computer network file system of claim 1, wherein said network fabric comprises a Fibre channel network.

25. The computer network file system of claim 1, wherein said network fabric comprises an ethernet network.

26. The computer network file system of claim 1, wherein said network fabric comprises an asynchronous transfer mode network.

27. The computer network file system of claim 1, wherein said network fabric comprises a first Fibre channel network and wherein said first file server communicates with one or more disk drives using a second Fibre channel network.

28. The computer network file system of claim 1, wherein files stored by said first file server and files stored by said second file server are located in a hierarchical directory structure having a common root directory, said first file system information comprising directory information that describes directories stored on said first file server, said second file system information comprising directory information that describes directories stored on said second file server, said first directory information comprising location information for finding said second directory information, said location information comprising a server id that identifies said second file server.

29. The computer network file system of claim 1, wherein files stored by said first file server and files stored by said second file server are located in a hierarchical directory structure having a common root directory, said first file system information comprising metadata for locating files stored on said second file server.

30. The computer network file system of claim 1, wherein said first file system information comprises first metadata that describes directories stored on said first file server, said file system information comprising second metadata that describes directories stored on said second file server, said first metadata comprising location information for locating said second metadata, said location information comprising a server id.

31. The computer network file system of claim 30, wherein said first metadata comprises a root directory.

32. The computer network file system of claim 30, wherein at least said first metadata comprises file attributes for one or more files stored by said first file server.

33. The computer network file system of claim 30, wherein at least said first metadata comprises information to specify a selected logical disk block of a selected file and information to specify a disk that contains said selected logical block.

34. The computer network file system of claim 30, wherein said metadata identifies data blocks and parity blocks corresponding to said data blocks.

35. The computer network file system of claim 30, wherein said metadata identifies parity groups, said parity groups comprising a plurality of information blocks, said information blocks comprising one or more data blocks, said information blocks further comprising a parity block, each of said information blocks stored on a different disk drive.

36. The computer network file system of claim 1, wherein a size of a first parity group is independent of a size of a second parity group.

37. The computer network file system of claim 1, wherein said first file server communicates with one or more disk drives using a Fibre channel network.

38. The computer network file system of claim 1, wherein said first file server communicates with one or more disk drives using InfiniBand.

39. The computer network file system of claim 1, wherein said first file server communicates with one or more disk drives using SCSI.

40. The computer network file system of claim 1, wherein said first file server is configured to mirror one or more files owned by said second file server, and said second file server is configured to mirror one or more files owned by said first file server,

41. A method for storing data in a computer network, comprising:

loading first file system metadata on a first file server operably connected to a network fabric;

loading second file system metadata on a second file server connected to said network fabric, said first file system metadata and said second file system metadata comprising information to allow a client computer operably connected to said network fabric to locate a file stored by said first file server or stored by said second file server without prior knowledge as to which file server stores said file;

maintaining information on said second file server to enable said second file server to reconstruct an information content of said first file system metadata; and

maintaining information on said first file server to enable said first file server to reconstruct an information content of said second file system metadata.

42. The method of claim 41, further comprising storing first file system directory information on said first file server, said first file system directory information describing a directory structure of a portion of the network file system whose directories are stored on said first file server, said first file system directory information comprising location information for a first file, said location information comprising a server id that identifies a file server containing said first file.

43. The method of claim 41, further comprising storing first file system directory information on said first file server, said first file system directory information describing a directory structure of a portion of the network file system whose directories are stored on said first file server, said first file system directory information comprising location information for a first file, said location information comprising a server id that identifies said second file server.

44. The method of claim 43, wherein said first file system directory information comprises a root directory.

45. The method of claim 41, wherein said first file system metadata comprises file system directory information that comprises at least one Gnid-string.

46. The method of claim 45, wherein a correspondence exists between said at least one Gnid-string and a directory stored on said first file server.

47. The method of claim 45, wherein said Gnid-string comprises a collection of gnids.

48. The method of claim 47, wherein each of said gnids comprises information for locating a specified gnode.

49. The method of claim 48, wherein said information for locating a specified gnode comprises a pointer to said specified gnode.

50. The method of claim 49, wherein said specified gnode comprises file attributes for a file corresponding to said gnode.

51. The method of claim 50, wherein said file attributes include at least one of a file id, a file access time, a file creation time, and a file modification time.

52. The method of claim 49, wherein said specified gnode comprises information for locating a first gee of a plurality of gees corresponding to said gnode.

53. The method of claim 52, wherein said plurality of gees comprises gnode gees and data gees.

54. The method of claim 53, wherein each of said gnode gees comprises information to specify a logical block extent.

55. The method of claim 53, wherein each of said data gees comprises information to specify a first logical disk block and information to specify a disk that contains said first logical block.

56. The method of claim 53, further comprising defining a plurality of parity gees.

57. The method of claim 56, wherein each of said parity gees comprises information regarding location of parity data for one or more preceding data gees in said plurality of gees.

58. The method of claim 41, further comprising defining at least one parity group having a first parity group size, said at least one parity group comprising a parity block and one or more data blocks.

59. The method of claim 58, further comprising storing each of said data blocks and said parity block on different disk drives.

60. The method of claim 58, further comprising defining at least one parity group having a second parity group size.

61. The method of claim 41, further comprising:

mirroring said first file system directory information on said second file server.

62. The method of claim 41, wherein first file system directory information describes at least a portion of a hierarchical directory structure, said hierarchical directory structure spanning said first file server and said second file server, said first file system directory information comprising directory information that describes directories stored on said first file server, and wherein second file system directory information at least a portion of said hierarchical directory structure comprising directory information that describes directories stored on said second file server, said first directory information comprising location information for finding said second directory information, said location information comprising a server id that identifies said second file server.

63. The method of claim 41, wherein first file system directory information comprises first metadata that describes directories stored on said first file server, and wherein second file system directory information comprising second metadata that describes directories stored on said second file server, said first metadata comprising location information for locating said second metadata, said location information comprising a server id, said first metadata and said second metadata describing at least a portion of a hierarchical directory structure that spans both said first file server and said second file server.

64. The method of claim 63, wherein said first metadata comprises a root directory.

65. The method of claim 63, wherein at least said first metadata comprises file attributes for one or more files stored by said first file server.

66. The method of claim 63, wherein at least said first metadata comprises information to specify a selected logical disk block of a selected file and information to specify a disk that contains said selected logical block.

67. The method of claim 63, wherein said metadata identifies data blocks and parity blocks corresponding to said data blocks.

68. The method of claim 41, further comprising performing a directory lookup by sending a directory lookup request to said first file server, said first file server returning a directory file handle that points to a directory on said second file server.

69. The method of claim 41, further comprising sending intent information from said first file server to said second file server, said intent information describing changes to be made to said first file system metadata.

70. A computer network file system, comprising:

a first file server operably connected to a network fabric, said first file server storing a first plurality of files;

a second file server operably connected to the network fabric, said second file server storing a second plurality of files, said first file server storing a copy of said second plurality of files, said second file server storing a copy of said first plurality of files; and

means for locating files stored by said first file server and files stored by said second file server by traversing a directory structure that spans at least a said first file server and said second file server.

71. The computer network file system of claim 70, wherein said directory structure comprises location information for a first file, said location information comprising a server id that identifies at least said first file server or said second file server.

72. The computer network file system of claim 70, wherein said directory structure comprises server ids of servers that contain sub-directories.