Methods and apparatus for changing versions of a filesystem

• US 8,620,970 B2
• Filed: 10/03/2006
• Issued: 12/31/2013
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: English, Robert, Kesavan, Ram
• Primary Examiner(s): Lin, Shew-Fen
• Assistant Examiner(s): MINCEY, JERMAINE A
• Application Number:
  US11/542,777
• Publication Number:
  US 20080082589A1
• Time in Patent Office: 2,646 Days
• Field of Search: 707/204
• US Class Current: 707/809
• CPC Class Codes: G06F 16/116 Details of conversion of file system types or formats
• CPC Class Codes: G06F 16/119 Details of migration of file systems migration mechanisms in storage systems G06F3/0647
• 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

Abstract

A filesystem can be converted to a different version by creating a new data structure according to a new format of the different version and transforming the data from the filesystem to the new data structure. Transforming the data can include changing the format of the data in the filesystem to be compatible with the new data structure format. The data may be incorporated into the new data structure by copying the data, or creating indirect reference mechanisms to point to the original data.

Claims

1. A method for converting a first filesystem in a network storage server to a second filesystem, the method comprising:

generating, in response to an upgrade or revert command from a transformer module to convert a requested portion of the first filesystem, a new logical data structure representing a new logical organization of physical storage resources of the network storage server for the second filesystem in free space of an original logical data structure representing an original logical organization of the physical storage resources associated with the first filesystem in the network storage server, the first filesystem and second filesystem each including a set of procedures by which the network storage server can manage data storage, the second filesystem storing and managing units of user data in data blocks that are a smallest unit of user data that can be independently manipulated by the second filesystem, the original logical data structure formatted according to a first format corresponding to the first filesystem, the new logical data structure formatted according to a second format corresponding to the second filesystem;

determining the data block size of the first filesystem and the data block size of the second filesystem, wherein the second format corresponding to the second filesystem has a data block size that is larger than a data block size of the first format corresponding to the first filesystem, or has a data block size that is not an exact multiple of the data block size of the first format, or both;

in response to determining the data block size of the second filesystem is an exact multiple of the data block size of the first filesystem, adjusting the storage of the data block of the first system into a compatible multiple of data blocks of the second filesystem;

in response to determining the data block size of the second filesystem is not an exact multiple of the data block size of the first filesystem, copying data from the first filesystem space to the second filesystem; and

incorporating data from the original logical data structure into the new logical data structure in the second format to convert the first filesystem to the second filesystem, wherein the second filesystem is of a different filesystem version or filesystem type from the first filesystem, and wherein the second filesystem is available to serve data requests during the incorporating.

2. A method according to claim 1, wherein the new logical data structure comprises a volume.

3. A method according to claim 1, wherein incorporating data from the original logical data structure into the new logical data structure to convert the first filesystem to the second filesystem comprises performing a filesystem upgrade from a former version to an updated version.

4. A method according to claim 1, wherein incorporating data from the original logical data structure into the new logical data structure to convert the first filesystem to the second filesystem comprises performing a filesystem revert to revert from an updated version to a former version.

5. A method according to claim 1, wherein incorporating data from the original logical data structure into the new logical data structure in the second format to convert the first filesystem to the second filesystem comprises performing data replication of the first filesystem having a data structure that is incompatible with a storage server.

6. A method according to claim 1, further comprising:

determining that a data block of the original logical data structure is unused; and

deleting the unused data block from the original logical data structure.

7. A method according to claim 6, further comprising:

incorporating the data block deleted from the original logical data structure into the new logical data structure as available storage after deleting the data block from the original logical data structure.

8. A method according to claim 1, wherein incorporating the data from the original logical data structure to the new logical data structure includes:

generating a pointer in the new logical data structure to point to the storage space of the data of the original logical data structure; and

deleting reference to the data in the original logical data structure.

9. A method according to claim 1, wherein incorporating the data from the original logical data structure to the new logical data structure includes:

copying data blocks from the original logical data structure into data blocks sized to be a scaled ratio of the data block sizes of the second format.

10. A method according to claim 1, wherein incorporating the data from the original logical data structure to the new logical data structure includes:

reading the data of the original logical data structure;

converting the data into the second format; and

storing the data in storage space managed by the new logical data structure.

20. A method according to claim 1, wherein the original logical data structure comprises a volume.

21. A method according to claim 1, further comprising creating a sparse volume in the free space of the first filesystem, wherein generating a new logical data structure for the second filesystem in free space of an original logical data structure of the first filesystem comprises generating absent blocks in the sparse volume to point to data of the first filesystem.

22. A method according to claim 1, wherein said method is performed in a background process of the network storage server which is not disruptive to servicing of client-initiated data access requests by the network storage server.

26. The method of claim 1, wherein the first filesystem and the second filesystem are each configured to execute read/write operations on the respective original logical data structure and new logical data structure.

11. An article of manufacture comprising a machine-accessible storage medium storing content to provide instructions, which when executed result in a machine performing a process including:

creating, in response to an upgrade or revert command from a transformer module to convert a requested portion of an original filesystem, a new filesystem in free space of the original filesystem including building in the free space one or more logical data structures representing a logical organization of physical storage resources, the original filesystem and new filesystem each including a set of procedures by which a processing device can manage data storage, the new filesystem stores and manages units of user data in data blocks that are a smallest unit of user data that can be independently manipulated by the new filesystem, the new filesystem having a new format different from the original filesystem to manage data access to the free space in accordance with the new format of the new filesystem;

determining the data block size of the original filesystem and the data block size of the new filesystem, the new format having a data block size that is larger than a data block size of an original format of the original filesystem, or having a data block size that is not an exact multiple of the data block size of the original format, or both;

in response to determining the data block size of the new filesystem is an exact multiple of the data block size of the original filesystem, adjusting the storage of the data block of the first system into a compatible multiple of data blocks of the new filesystem; and

in response to determining the data block size of the new filesystem is not an exact multiple of the data block size of the original filesystem, iteratively copying data of the original filesystem, converting the data to the new format of the new filesystem, and incorporating the data from the original filesystem into the free space managed by the new filesystem.

12. An article of manufacture according to claim 11, wherein creating the new filesystem comprises creating a sparse volume in the free space of the original filesystem, and wherein incorporating the data from the original filesystem into the free space comprises generating absent blocks to point to data of the original filesystem.

13. An article of manufacture according to claim 11, wherein converting the data to the new format of the new filesystem comprises copying data from a block size incompatible with the new format of the new filesystem to a block size compatible with the new format of the new filesystem.

14. An article of manufacture according to claim 11, wherein deleting the converted data comprises removing the data space of the deleted data from the original filesystem and making the data space available to the new filesystem.

23. An article of manufacture according to claim 11, wherein said process is a background process of the machine.

15. A storage server comprising:

an original filesystem having an original virtual data structure representing an original grouping of physical storage resources of the storage server, the original filesystem having free space and an original kernel providing an original format and organization standards of the original filesystem;

a new filesystem having a new virtual data structure representing a new grouping of the physical storage resources of the storage server, the new filesystem having a new format and configured to store and manage units of data in data blocks that are a smallest unit of user data that can be independently manipulated by the new filesystem, the new filesystem located in the new virtual data structure in the free space of the original filesystem, and the new format having a data block size that is larger than a data block size of the original format, or having a data block size that is not an exact multiple of the data block size of the original format, or both; and

a transformer module to generate an upgrade or revert command to convert a requested portion of the original filesystem to the new filesystem, to generate the new filesystem and to transform the data from the original virtual data structure of the original filesystem into the new virtual data structure according to the new format by determining the data block size of the original filesystem and the data block size of the new filesystem, and in response to determining the data block size of the new filesystem is an exact multiple of the data block size of the first filesystem, adjusting the data block of the original system into a compatible multiple of data blocks of the new filesystem, and in response to determining the data block size of the new filesystem is not an exact multiple of the data block size of the original filesystem, copying data from the original filesystem space to the second filesystem space, the original filesystem and new filesystem each including a mechanism by which the storage server can manage data storage, wherein the storage server is configured to make available the new filesystem to serve data requests during the transforming.

16. A storage server according to claim 15, wherein the transformer module comprises a new kernel to execute the new filesystem according to the new format, and a translation module to convert the data from the original filesystem to the new filesystem.

17. A storage server according to claim 16, the translation module to further iteratively step through the original virtual data structure of the original filesystem and convert the original virtual data structure block-by-block into the new format to be stored in the new virtual data structure.

18. A storage server according to claim 15, wherein to transform the data into the new virtual data structure according to the new format comprises to create a pointer to the data of the original virtual data structure, the pointer to be stored in the new virtual data structure.

19. A storage server according to claim 15, wherein to transform the data into the new virtual data structure according to the new format comprises to copy data from the original virtual data structure of the original filesystem of one block size into data blocks of a different size.

24. A storage server according to claim 15, wherein the transformer module is configured to:

create a sparse volume in the free space of the original filesystem; and

generate absent blocks in the sparse volume to point to data of the original filesystem.

25. A storage server according to claim 15, wherein the transformer module is configured to generate the new filesystem and transform the data from the original virtual data structure of the original filesystem into the new virtual data structure in a background process of the storage server which is not disruptive to servicing of client-initiated data access requests by the storage server.