Redundancy for storage data structures

• US 7,533,330 B2
• Filed: 06/27/2005
• Issued: 05/12/2009
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Anderson, David, Yang, Xueshi, Iren, Sami
• Primary Examiner(s): Abraham; Esaw T
• Application Number:
  US11/167,774
• Publication Number:
  US 20080010580A1
• Time in Patent Office: 1,415 Days
• Field of Search: 714/6, 714/710, 714/711, 714/763, 714/799, 714/48, 714/758
• US Class Current: 714/799
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: G11B 2220/2516 Hard disks

Abstract

A storage device comprising has a storage medium, a read-write mechanism, an object-based file system interface, and a controller. The read-write mechanism is adapted to read and to write data from and to the storage medium. The object-based file system interface within the storage device is adapted to organize and access data on the storage medium as objects and to access attributes of each data object. The controller is adapted to generate redundancy data for each data object to be stored on the storage medium according to the associated attributes and to store the data object and its associated redundancy data on the storage medium.

Claims

1. A storage device comprising:

a storage medium;

read write circuitry adapted to read and write data objects from and to the storage medium;

an object-based file system interface within the storage device adapted to organize and access data on the storage medium as objects, the object-based file system interface adapted to access attributes associated with each data object; and

a controller adapted to control access to the storage medium through the read-write circuitry, the controller adapted to selectively apply different levels of redundancy to generate redundancy data for each data object to be stored on the storage medium according to the associated attributes and to store the data object at a first allocated area on the storage medium and its associated redundancy data at a second allocated area on the storage medium;

wherein the controller is adapted to selectively apply at least one redundancy algorithm to each data object to generate its associated redundancy data.

2. The storage device of claim 1 wherein the controller further comprises:

a memory adapted to temporarily store changes to a stored data object when the stored data object is changed, wherein the controller is adapted to generate associated redundancy data based on changes to the data object and to store the generated redundancy data at a particular allocate area on the storage medium.

3. The storage device of claim 1 wherein, each time a particular data object is accessed, the controller accesses the associated redundancy data for the particular data object, the controller adapted to use the accessed redundancy data to recover the data object if an error is detected.

4. The object-based storage device of claim 1 wherein the controller is adapted to apply different redundancy algorithms to a particular object and its sub-fields for a desired level of protection according to the associated attributes of the particular object.

5. The object-based storage device of claim 1 wherein the controller is adapted to:

select a redundancy algorithm from a plurality of redundancy algorithms based on at least one attribute of an object to be stored on the storage medium and to generate the redundancy data according to the selected redundancy algorithm.

6. The storage device of claim 1, wherein attributes comprise at least one of static information about the object, dynamic information that is updated each time the object is accessed, application specific information, and user information.

7. A storage device comprising:

a storage medium;

an object-based file system interface within the storage device adapted to access attributes of each data object and to derive information about contents of each data object from the accessed attributes, the object-based file system adapted to allocate space on the storage medium for a particular data object to be stored based on accessed attribute information and to allocate first space on the storage medium for storage of the particular data object and to allocate second space on the storage medium for storage of the redundancy data associated with the particular data object;

read-write circuitry coupled to the storage medium adapted to read and write data objects from and to allocated space on the storage medium; and

a controller adapted to;

determine at least one desired level of error protection for the particular data object based on the accessed attributes;

generate redundancy data for the particular data object to be stored on the storage medium according to the desired level of error protection; and

control the read-write circuitry to store the particular data object at the first space and the generated redundancy data at the second space;

wherein the controller is adapted to select different redundancy algorithms with different levels of data protection for data objects and their sub-fields according to a desired level of protection.

8. The storage device of claim 7 wherein the data object and its associated redundancy data are stored on the storage medium as separate entities.

9. The storage device of claim 7 further comprising:

a memory coupled to the controller and adapted to store a plurality of redundancy algorithms;

wherein the controller is adapted to select a redundancy algorithm from the plurality of redundancy algorithms based on an attribute associated with the particular data object to achieve the desired level of protection, the controller to apply the selected redundancy algorithm to generate the associated redundancy data.

10. The storage device of claim 7 wherein the storage device comprises a RAID storage system and wherein the associated redundancy data is stored across multiple discs of the RAID storage system.

11. The storage device of claim 7, wherein the controller selects a first redundancy algorithm to generate first redundancy data related to metadata of the particular data object and selects a second redundancy algorithm to generate second redundancy data related to other data of the particular data object, wherein the first redundancy algorithm provides a greater level of protection for data loss relative to the second redundancy algorithm.

12. A method for providing redundant protection for data objects stored on a storage device, the method comprising:

accessing attributes of-a data object to be stored on a storage medium of an object-based storage device without accessing a data structure portion of the data object using an object-based file system interface within the object-based storage device;

selecting at least one redundancy algorithm from a plurality of redundancy algorithms to achieve a desired level of protection for a data object based on the accessed attributes;

generating redundancy data from the data object using the selected at least one redundancy algorithm by applying selected redundancy algorithms for desired error protection and reliability to the data object and its sub-elements according to the attributes of the data object;

allocating first and second spaces for the data object and for the generated redundancy data, respectively, on the storage medium using the object-based file system interface; and

writing the data object to the first space and the generated redundancy data to the second space on the storage medium using read-write circuitry of the object-based storage device.

13. The method of claim 12 further comprising:

accessing the redundancy data each time the data object is accessed.

14. The method of claim 12 wherein before the step of generating, the method further comprises:

determining a desired level of protection for the data object based on the accessed attributes of the data object; and

selecting the redundancy algorithm from a plurality of redundancy algorithms based on the desired level of protection.

15. The method of claim 12 wherein if the stored data object is later retrieved and modified, the method further comprising:

calculating modified redundancy data for the modified data object; and

storing the modified data object and the modified redundancy data on the storage medium.

16. The method of claim 12 wherein the redundancy data provides a level of protection based on the logical boundary of each data object.

17. The method of claim 12, wherein selecting at least one redundancy algorithm comprises:

determining a first quality of service (QoS) associated with a first portion of the particular data object;

determining a second quality of service (QoS) associated with a second portion of the particular data object; and

selecting a first redundancy algorithm based on the first QoS;

selecting a second redundancy algorithm based on the second QoS; and

generating redundancy data for the first portion of the particular data object using the first redundancy algorithm; and

generating redundancy data for the second portion of the particular data object using the second redundancy algorithm;

wherein the first and second portions and the first and second QoS are determined by accessing attributes of the data object.