MULTI-TIER STORAGE USING MULTIPLE FILE SETS

• US 20130275653A1
• Filed: 04/13/2012
• Published: 10/17/2013
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Ranade, Dilip Madhusudan, Pendharkar, Niranjan
• Granted Patent: US 11,347,443 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/1734 Details of monitoring file system events, e.g. by the use of hooks, filter drivers, logs
• CPC Class Codes: G06F 16/174 Redundancy elimination performed by the file system management of the data involved in backup or backup restore using de-duplication of the data G06F11/14
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: G06F 16/185 Hierarchical storage management [HSM] systems, e.g. file migration or policies thereof details of archiving G06F16/11
• CPC Class Codes: G06F 16/2282 Tablespace storage structures; Management thereof
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0649 Lifecycle management
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Storage locations in a first tier of a multi-tier storage system are allocated to a first set of data structures (e.g., inodes) in a first file set. A file that is stored in the first tier is associated with a first data structure of the first set. In response to determining that data in the file should be moved to a second tier of the multi-tier storage system, the file is associated with a second data structure in a second file set. The second data structure is allocated a storage location in the second tier. Consequently, two data structures are associated with the file. The data is copied from the first tier to the storage location in the second tier, and can be subsequently accessed using the second data structure.

Claims

1. A computer-readable storage medium having computer-executable instructions for causing a computer system to perform a method comprising:

allocating storage locations in a first tier of a multi-tier storage system to a first plurality of data structures in a first file set, wherein each of said data structures comprises information about a respective file and maps a file to memory block addresses;

associating a file that is stored in said first tier with a first data structure of said first plurality of data structures;

in response to a determination that data in said file is to be moved to a second tier of said multi-tier storage system, associating said file with a second data structure in a second file set wherein two data structures are associated with said file, wherein further said second data structure is allocated a storage location in said second tier; and

copying said data from said first tier to said storage location in said second tier.

2. The computer-readable storage medium of claim 1 wherein said first data structure and said second data structure are identified using identical identifiers.

3. The computer-readable storage medium of claim 1 wherein said first data structure and said second data structure have different identifiers.

4. The computer-readable storage medium of claim 1 wherein said method further comprises setting a flag associated with said first data structure to indicate presence of said second data structure.

5. The computer-readable storage medium of claim 1 wherein said method further comprises including reference to said second data structure in said first data structure.

6. The computer-readable storage medium of claim 1 wherein said method further comprises checking state information associated with said file to determine whether or not said file is a candidate for movement from one tier of said multi-tier storage system to another tier of said multi-tier storage system.

7. The computer-readable storage medium of claim 6 wherein said checking is performed in response to an event selected from the group consisting of:

an access to said file; and

expiration of a specified time period.

8. The computer-readable storage medium of claim 1 wherein one of said first and second tiers comprises a higher ranking tier relative to the other of said first and second tiers, wherein said method further comprises, in response to a request to access said file, checking said higher ranking tier for a data structure associated with said file before checking the lower ranking tier.

9. The computer-readable storage medium of claim 1 wherein one of said first and second tiers comprises a higher ranking tier relative to the other of said first and second tiers, wherein said method further comprises, in response to determining that available storage capacity of said higher ranking tier is below a threshold value, checking state information only for data structures for said higher ranking tier to identify files that are candidates to be moved to the lower ranking tier.

10. A computer system comprising:

a processor; and

memory coupled to said processor and having stored therein instructions that, if executed by said computer system, cause said computer system to execute operations comprising;

determining that data in a file is to be moved from a first tier of a multi-tier storage system to a second tier of said multi-tier storage system, wherein storage locations in said first tier are allocated to a first plurality of inodes in a first file set and wherein said file is associated with a first inode of said first plurality of inodes;

associating said file with a second inode of a second plurality of inodes in a second file set wherein two inodes are associated with said file, and wherein further said second plurality of inodes are allocated storage locations from said second tier; and

copying said data from said first tier to a storage location in said second tier and allocated to said second inode.

11. The computer system of claim 10 wherein said first inode and said second inode have identical inode numbers, and wherein said operations further comprise setting a flag associated with said first inode to indicate presence of said second inode.

12. The computer system of claim 10 wherein said first inode and said second inode have different inode numbers, and wherein said first inode includes reference to said second inode.

13. The computer system of claim 10 wherein said operations further comprise checking state information associated with said file to determine whether or not said file is a candidate for movement from one tier of said multi-tier storage system to another tier of said multi-tier storage system.

14. The computer system of claim 13 wherein said checking is performed in response to an event selected from the group consisting of:

an access to said file;

expiration of a specified time period; and

available storage capacity in a tier falling below a threshold value.

15. A computer-implemented method comprising:

allocating storage locations in a first drive of a multi-drive storage system to a plurality of base data structures, wherein each of said base data structures comprises information about a respective region of data and maps a region of data to memory block addresses;

identifying a region of data in said first drive to be cached in a second drive of said multi-drive storage system, wherein said region is associated with a base data structure of said plurality of base data structures;

associating said region of data with an auxiliary data structure that is allocated a storage location in said second drive, wherein both said base data structure and said auxiliary data structure are associated with said region of data; and

caching said data from said first drive in said storage location in said second drive.

16. The method of claim 15 wherein said base data structure and said auxiliary data structure have identical identifiers, and wherein said method further comprises setting a flag associated with said base data structure to indicate presence of said auxiliary data structure.

17. The method of claim 15 wherein said base data structure and said auxiliary data structure have different identifiers, and wherein said base data structure includes reference to said auxiliary data structure.

18. The method of claim 15 further comprising checking state information associated with said auxiliary data structure to determine whether said storage location in said second drive is a candidate for cache invalidation.

19. The method of claim 15 further comprising:

in response to a read request for said data, querying said base data structure to determine whether said auxiliary data structure exists, said base data structure comprising information referencing said auxiliary data structure; and

using said auxiliary data structure to read said data from said storage location in said second drive.

20. The method claim 15 wherein said first drive comprises a hard disk drive and said second drive comprises a solid state drive.