Reduction in time required to write file to tape

Patent metadata

Field	Value
Publication number	US-10331628-B2
Application number	US-201715492240-A
Country	US
Kind code	B2
Filing date	Apr 20, 2017
Priority date	Apr 15, 2014
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Reducing time required to write a file to tape is provided. Synchronous processing is performed in a file system implementing a Linear Tape File System (LTFS) file format, wherein the synchronous processing includes writing, to a tape medium of a tape cartridge, index information and one or more files. A type of the synchronous processing is determined, wherein the type is either an index-MAM sync type or an index-only sync type. Updated information is stored to a media auxiliary memory of the tape cartridge in response to determining that the synchronous processing is of the index-MAM sync type.

First claim

What is claimed is:

1. A method of writing data in a file system including a Media Auxiliary Memory (MAM), the method comprising:
performing, in response to a trigger, synchronous processing in the file system, wherein the synchronous processing includes writing, to a tape medium of a tape cartridge, one or more files, and updating index information on the tape medium;
determining between two types of the synchronous processing, wherein the type is either an index-Media Auxiliary Memory (index-MAM) sync type or an index-only sync type, and wherein the type of synchronous processing is based on the trigger;
storing updated information to the media auxiliary memory of the tape cartridge in response to determining that the synchronous processing is of the index-MAM sync type wherein data is read from and written to the tape cartridge in units of fixed-length data sets;
storing a first file and a first index following the first file on a first data set on the tape medium, wherein the first index corresponds to the first file;
storing a second file and a second index following the second file on a second data set on the tape medium, wherein the second index corresponds to the second file, wherein the first data set is adjacent to the second data set; and
determining that the synchronous processing is of the index-only sync type based on an occurrence of periodic synchronous processing, wherein in response to determining that the synchronous processing is of the index-only sync type, not storing the updated information to the media auxiliary memory of the tape cartridge.

2. The method of claim 1 , wherein the index-only sync type is triggered in response to the synchronous processing being periodically performed by the file system.

3. The method of claim 2 , wherein the type of synchronous processing switches from the index-only sync type to the index-MAM sync type based on an occurrence of either of: the tape cartridge being mounted in a tape drive or the tape cartridge being removed from the tape drive.

4. The method of claim 1 , wherein the updated information includes information on a generation of index information recorded on the tape medium and a location of the index information on the tape medium.

5. The method of claim 1 , wherein the index-MAM sync type is triggered based on an occurrence of either of: the tape cartridge being mounted in a tape drive or the tape cartridge being removed from the tape drive.

6. The method of claim 5 , wherein the type of synchronous processing switches from index-MAM sync type to the index-only sync type in response to the synchronous processing being periodically performed by the file system.

7. The method of claim 5 , further comprising:
updating the media auxiliary memory after the tape cartridge is remounted in the tape drive and before one or more files are initially written to add an indication that index information stored in the media auxiliary memory of the tape cartridge is invalid.

8. The method of claim 1 , wherein the synchronous processing further includes:
comparing index information stored in the media auxiliary memory to index information stored in a data partition of the tape medium in the tape cartridge;
writing one or more files to the data partition; and
storing index information to an index partition of the tape medium, wherein the index partition is located separately from the data partition.

9. The method of claim 1 , the method further comprising: not storing updated information to the media auxiliary memory of the tape cartridge in response to determining the type of synchronous processing is of the index-only sync type.

10. A tape cartridge in which a tape medium is formatted to reduce a time required for synchronous processing performed by a file system, wherein: the synchronous processing includes writing, to the tape medium, one or more files, and updating index information to the tape medium, data is read from and written to the tape medium in units of fixed-length data sets, and the index information is stored in a data set on the tape medium in which a file that follows the index information is also stored, wherein the tape cartridge includes a media auxiliary memory (MAM) that stores updated index information, wherein the synchronous processing is either an index-MAM sync type or an index-only sync type, wherein updated information is stored to the MAM in response to the index-MAM sync type, and wherein the MAM is not updated in response to the index-only sync type a first file and a first index following the first file are stored on a first data set on the tape medium, wherein the first index corresponds to the first file, and a second file and a second index following the second file are stored on a second data set on the tape medium, wherein the second index corresponds to the second file, wherein the first data set is adjacent to the second data set; and
determining that the synchronous processing is of the index-only sync type based on an occurrence of periodic synchronous processing, wherein in response to determining that the synchronous processing is of the index-only sync type, not storing the updated information to the media auxiliary memory of the tape cartridge.

11. The tape cartridge of claim 10 , wherein the synchronous processing is of an index-MAM sync type.

12. A method comprising:
performing synchronous processing in a file system, wherein the synchronous processing includes writing, to a tape medium of a tape cartridge, one or more files, and updating index information on the tape medium, wherein data is read from and written to the tape cartridge in units of fixed-length data sets;
determining synchronous processing is of the index-Media Auxiliary Memory (index-MAM) sync type in response to the tape cartridge being mounted in a tape drive;
storing, in response to determining synchronous processing is of the index-MAM sync type, updated information to a media auxiliary memory of the tape cartridge;
transitioning, from index-MAM sync mode to index-only sync mode, in response to synchronous processioning being periodically performed;
storing, in response to determining that the synchronous processing is of the index-only sync type, a first file and a first index following the first file on a first data set on the tape medium, wherein the first index corresponds to the first file;
storing, in response to determining that the synchronous processing is of the index-only sync type, a second file and a second index following the second file on a second data set on the tape medium, wherein the second index corresponds to the second file; and
transitioning, in response to the tape cartridge being removed from the tape drive, from index-only sync mode to index-MAM sync mode.

Assignees

• IBM

Inventors

• Abe Atsushi
• Ishimoto Takeshi
• Oishi Yutaka

Classifications

• G06F3/065

  Replication mechanisms · CPC title

• G06F3/0608

  Saving storage space on storage systems · CPC title

• G06F16/13

  File access structures, e.g. distributed indices (arrangements of input from, or output to, record carriers G06F3/06) · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F16/178 Primary

  Techniques for file synchronisation in file systems · CPC title