File index, metadata storage, and file system management for magnetic tape

• US 9,430,155 B2
• Filed: 03/25/2010
• Issued: 08/30/2016
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Amir, Arnon, Pease, David A., Richter, Rainer
• Primary Examiner(s): Waldron, Scott A
• Assistant Examiner(s): SHECHTMAN, CHERYL MARIA
• Application Number:
  US12/732,158
• Publication Number:
  US 20110238716A1
• Time in Patent Office: 2,350 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1727 Details of free space management performed by the file system saving storage space on storage systems G06F3/0608; management of blocks in storage devices G06F3/064
• CPC Class Codes: G06F 16/1873 Versioning file systems, temporal file systems, e.g. file system supporting different historic versions of files
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0682 Tape device
• CPC Class Codes: G06F 3/0686 Libraries, e.g. tape libraries, jukebox
• CPC Class Codes: G11B 27/032 on tapes G11B27/036, G11B27/038 take precedence

Abstract

In one embodiment, a method for writing data to a magnetic recording tape includes writing a plurality of files to a first partition of a magnetic recording tape using a tape drive, and writing an index to a second partition of the magnetic recording tape using the tape drive, the index including information about locations of data of the plurality of files in the first partition of the magnetic recording tape.

Claims

1. A method for writing data to a magnetic recording tape, the method comprising:

writing a plurality of files to a first partition of a magnetic recording tape using a tape drive, file content being written in a first data partition in multiple linear tracks each having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape, the linear tracks being written in multiple wraps; and

writing an index to a second partition of the magnetic recording tape using the tape drive, the index including information about locations of data of the plurality of files in the first partition of the magnetic recording tape,

wherein the partitions are physically separate and independently addressable on the magnetic recording tape,

wherein the first partition is a longitudinal partition arranged longitudinally along the magnetic recording tape,

wherein the second partition is a longitudinal partition arranged longitudinally along the magnetic recording tape,

each partition comprising multiple wraps,

wherein the index in the second partition is aligned on the tape, in a direction perpendicular to the longitudinal axis of the magnetic recording tape, with at least one of the files in the first partition,

wherein the writing the plurality of files to the first partition is performed using shingled writing,

wherein a longitudinal buffering band is present between the first and second partitions, the longitudinal buffering band extending along shingled tracks of the first partition along the longitudinal axis of the magnetic recording tape, wherein the longitudinal buffering band is configured to isolate writing in the first partition from overwriting neighboring tracks in the second partition, and wherein the longitudinal buffering band comprises an entirety of at least one full wrap of the magnetic recording tape.

2. The method of claim 1, wherein, for each of the plurality of files in the first partition, the index further includes at least one of:

a file name, a file size, a file type, a date of creation, a date of last modification, a checksum of file content, and access information.

3. The method of claim 1, further comprising writing the following to the second partition:

a search index including information about data content of the plurality of files in the first partition; and

/or

an encryption key configured to encrypt the data of one or more of the files in the first partition.

4. The method of claim 1, further comprising writing a plurality of files to a third partition of the magnetic recording tape using the tape drive, wherein the index in the second partition of the magnetic recording tape includes information about locations of data of the plurality of files in the first and third partitions, wherein the second partition is a sole partition on the magnetic recording tape to which any index is written, wherein the first, second and third partitions each include an entirety of at least one full wrap of the magnetic recording tape.

5. The method of claim 1, wherein the index includes a hierarchical directory and structure of references to the plurality of files, wherein the method further comprises writing one or more metadata files to the second partition, wherein the one or more metadata files include information about at least one of the plurality of files on the first partition, wherein the one or more metadata files are positioned ahead of the index relative to a beginning of the second partition.

6. The method of claim 1, further comprising storing a copy of the index in the second partition and a nonvolatile memory coupled to a cartridge that houses the magnetic recording tape, wherein the copy of the index is an identical copy of the index.

7. The method of claim 6, further comprising:

writing a first updated version of the index to the second partition upon updating at least one of the plurality of files in the first partition, the updating the at least one of the plurality of files in the first partition including appending data to the plurality of files in the first partition, wherein the first updated version of the index is positioned after the index relative to a beginning of the second partition; and

storing at least one identical copy of the first updated version of the index in the second partition and the nonvolatile memory coupled to the cartridge.

8. The method of claim 7, further comprising accessing the index for retrieving one of the files or portion thereof that is not present in the first updated index.

9. The method of claim 7, further comprising:

determining whether the updating of the at least one of the plurality of files in the first partition and/or the writing of the first updated index was interrupted; and

rolling back the update of the at least one of the plurality of files and/or the first updated index upon determining that the updating of the at least one of the plurality of files and/or the writing of the first updated index was interrupted.

10. The method of claim 7, further comprising:

writing a second updated version of the index to the second partition upon a second updating of at least one of the plurality of files, the second updating of the at least one of the plurality of files including appending data to the plurality of data files in the first partition.

11. The method of claim 10, wherein writing the second updated version of the index to the second partition includes:

overwriting the index with the first updated version of the index and overwriting the first updated version of the index with the second updated version of the index.

12. The method of claim 6, further comprising writing, to the second partition and the nonvolatile memory of the cartridge, a thumbnail of at least one of the plurality of files in the first partition to support file visualization thereof.

13. A non-transitory computer program product for writing data to a magnetic recording tape, the computer program product comprising:

a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to write a plurality of files to a first partition of a magnetic recording tape in multiple linear tracks using a tape drive, each of the linear tracks having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape; and

computer readable program code configured to write an index to a second partition of the magnetic recording tape using the tape drive, the index including hierarchical directories in which are stored information about locations of data of the plurality of files in the first partition,

wherein the partitions are physically separate and independently addressable longitudinal partitions arranged longitudinally along the magnetic recording tape,

wherein each partition comprises one or more wraps of the magnetic recording tape,

wherein a longitudinal buffering band comprising at least one wrap of the magnetic recording tape is present between the first partition and second partition and extends along the linear tracks written in the first partition, the longitudinal buffering being configured to isolate writing in the first partition from overwriting neighboring tracks in the second partition.

14. A method, comprising:

storing a plurality of files in a first data partition of a magnetic recording tape using a tape drive, the plurality of files being written in the first data partition in multiple linear tracks each having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape, the linear tracks being written in multiple wraps;

storing an index in a second data partition of the magnetic recording tape using the tape drive, the index comprising at least two file attributes for each file in the first data partition, where the file attributes are selected from a group consisting of;

a file name, a file size, a file type, a date of creation, a date of last modification, a checksum of file content, a location of the file and/or portions thereof in the first partition, and access information;

storing a search index in the second data partition of the magnetic recording tape using the tape drive, the search index including information about data content of the plurality of files in the first data partition; and

retrieving a desired portion of file content stored in the first data partition using the index and/or the search index,

wherein the first and second data partitions are physically separate and independently addressable on the magnetic recording tape,

wherein the index in the second data partition is aligned on the tape, in a direction perpendicular to the longitudinal axis of the magnetic recording tape, with at least one of the files in the first data partition,

wherein a buffering band comprising an entirety of at least one full wrap of the magnetic recording tape is positioned between the first and second data partitions.

15. A method for formatting a magnetic recording tape, comprising:

formatting a first partition and a second partition on a magnetic recording tape using a tape drive, wherein the first partition is formatted for writing file content in multiple parallel wraps of linear tracks each having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape;

writing an initial index to the second partition, the initial index comprising file content indexing information, the index being stored on the second partition as an XML index file with a plurality of name-value pairs;

selecting whether a file is to be written to the first partition and/or the second partition based on one or more rules stored in the index,

wherein the first and second partitions are longitudinal partitions arranged longitudinally along the magnetic recording tape, and are physically separate and independently addressable on the magnetic recording tape; and

wherein a longitudinal buffering band of one or more wraps is present between the first partition and the second partition, and extends along the linear tracks of the first partition.

16. The method of claim 15, further comprising:

creating a plurality of copies of the initial index and storing the copies in one of the partitions and a nonvolatile memory coupled to a cartridge that houses the magnetic recording tape; and

creating thumbnails of the file content in the first partition and storing the thumbnails in the second partition and the nonvolatile memory coupled to the cartridge.

17. The method of claim 15, further comprising writing, in addition to the index, a search index to the second partition, the search index including information about data content of each of the plurality of files on the magnetic recording tape.

18. The method of claim 15, wherein first partition, the second partition and the longitudinal buffering band each include a plurality of wraps extending a length of the magnetic tape.

19. A method, comprising:

storing file content in at least two data partitions of a magnetic recording tape using a tape drive, the file content being stored in each data partition in multiple linear tracks each having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape, the linear tracks being written in multiple wraps;

storing an index in an index partition of the magnetic recording tape using the tape drive, the index comprising indexing information associated with the file content in the data partitions;

performing a first update of the file content stored in at least one of the data partitions by appending a first set of new content at an end of the file content therein and writing an first updated version of the index; and

performing a second update of the file content stored in at least one of the data partitions by appending a second set of new content at an end of the first set of new content therein and writing a second updated version of the index, wherein writing the second updated version of the index comprises;

physically overwriting the index with the first updated version of the index, and physically overwriting the first updated version of the index with the second updated version of the index;

wherein a longitudinal buffering band of one or more wraps is present between the first partition and the second partition, and extends along the linear tracks of the first partition.

20. The method of claim 19, wherein the performing of the first update of the index includes modifying an extents list of the file content by removing portions of extents deleted by the file content updating and adding new extents to the extents list, wherein the first updated index is positioned after the index relative to a beginning of the index partition.

21. The method of claim 19, further comprising generating and storing a search index in the index partition by analyzing and indexing the file content stored in the data partitions, wherein the search index is updated when data is appended to the file content stored in at least one of the data partitions.

22. The method of claim 19, further comprising storing multiple copies of the index, the first updated index, and the second updated index on the index partition and/or a nonvolatile memory coupled to a cartridge that houses the magnetic tape.

23. The method of claim 22, further comprising storing, in the index partition and the nonvolatile memory of the cartridge, thumbnails of the file content in each data partition.

24. The method of claim 19, further comprising determining whether performing an update of the file content and/or the index was interrupted;

and rolling back a last update of the file content and/or the index upon determining that the performing of an update of the file content and/or the index was interrupted.

25. A method for reading data from a magnetic recording tape having at least two partitions, the method comprising:

reading an index stored on a first partition of a magnetic recording tape using a tape drive;

finding locations of a plurality of file portions on the magnetic recording tape using the index; and

reading the file portions from a second partition of the magnetic recording tape using the tape drive, the file portions being stored in the second partition in multiple linear tracks each having a longitudinal axis oriented parallel to a longitudinal axis of the magnetic recording tape, the linear tracks characterized as having been written in multiple wraps,

wherein the partitions are physically separate and independently addressable on the magnetic recording tape,

wherein the partitions are longitudinal partitions, each partition comprising one or more wraps extending a length of the magnetic recording tape,

wherein a longitudinal buffering band comprising one or more wraps extending the length of the magnetic recording tape is present between the first partition and the second partition,

wherein the index in the first partition is aligned on the tape, in a direction perpendicular to the longitudinal axis of the magnetic recording tape, with at least one of the files in the second partition.