Grouped-object RAID

• US 20050160309A1
• Filed: 01/05/2004
• Published: 07/21/2005
• Est. Priority Date: 01/05/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Golding, Richard Andrew
• Granted Patent: US 7,100,073 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0667 at data level, e.g. file, record or object virtualisation
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A RAID-configured grouped-object storage system provides reduced storage space overhead for small objects. The storage system includes a plurality stripes arranged across a plurality of physical objects. Each stripe includes a plurality of storage blocks that are each mapped on to a respectively different physical object. The storage system also includes a plurality of virtual objects each containing at least one storage block. A group of virtual objects is formed when a virtual object contains less storage blocks than the number of stripes by associating the virtual object with at least one virtual object containing less storage blocks than the number of stripes and/or at least one storage block containing zero values so that the storage blocks of each group of virtual objects equals the number of stripes. The storage blocks of each virtual object and of each group of virtual objects are mapped to a respectively different stripe.

Claims

1. A grouped-object storage system, comprising:

a plurality of physical objects;

a first predetermined number of stripes arranged across the plurality of physical objects, each stripe containing a second predetermined number of storage blocks, the second predetermined number of storage blocks in each stripe corresponding to a number of physical objects of the plurality of physical objects, one storage block of the second predetermined number of storage blocks in a stripe containing redundancy information for the stripe, the storage block containing redundancy information for a stripe and each other storage block of the stripe being mapped on to a respectively different physical object; and

a plurality of virtual objects, each virtual object containing between one and first predetermined number of storage blocks, a group of virtual objects being formed when a virtual object contains less than the first predetermined number of storage blocks by associating the virtual object with at least one of at least one virtual object containing less than the first predetermined number of storage blocks and at least one storage block containing zero values so that each group of virtual objects contains the first predetermined number of storage blocks, the storage blocks of each virtual object containing the predetermined number of storage blocks being mapped to a respectively different stripe, and the storage blocks of each group of virtual objects being mapped to a respectively different stripe.

2. The grouped-object storage system according to claim 1, wherein each virtual object is a same size.

3. The grouped-object storage system according to claim 1, wherein at least one virtual object is a size that is different from a size of at least one other virtual object.

4. The grouped-object storage system according to claim 1, wherein the grouped-object storage system is configured to have RAID level 5 protection.

5. The grouped-object storage system according to claim 1, wherein the grouped-object storage system is configured to have RAID level 6 protection.

6. The grouped-object storage system according to claim 1, wherein the physical objects are stored on a plurality of object storage devices.

7. The grouped-object storage system according to claim 6, wherein at least one object storage device is a tape drive.

8. The grouped-object storage system according to claim 6, wherein at least one object storage device is a random access memory device.

9. The grouped-object storage system according to claim 6, wherein at least one object storage device is an optical storage drive.

10. The grouped-object storage system according to claim 6, wherein at least one object storage device is a hard disk drive.

11. A method of forming a grouped-object storage system, the method comprising:

forming a plurality of physical objects;

arranging a first predetermined number of stripes across the plurality of physical objects, each stripe containing a second predetermined number of storage blocks, the second predetermined number of storage blocks in each stripe corresponding to a number of physical objects of the plurality of physical objects, one storage block of the second predetermined number of storage blocks in a stripe containing redundancy information for the stripe, the storage block containing redundancy information for a stripe and each other storage block of the stripe being mapped on to a respectively different physical object;

forming a plurality of virtual objects, each virtual object containing between one and first predetermined number of storage blocks;

forming a group of virtual objects when a virtual object contains less than the first predetermined number of storage blocks by associating the virtual object with at least one of at least one virtual object containing less than the first predetermined number of storage blocks and at least one storage block containing zero values so that each group of virtual objects contains the first predetermined number of storage blocks;

mapping the storage blocks of each virtual object containing the predetermined number of storage blocks to a respectively different stripe; and

mapping the storage blocks of each group of virtual objects to a respectively different stripe.

12. The method according to claim 11, wherein each virtual object is a same size.

13. The method according to claim 11, wherein at least one virtual object is a size that is different from a size of at least one other virtual object.

14. The method according to claim 11, further comprising configuring the grouped-object storage system to have RAID level 5 protection.

15. The method according to claim 11, further comprising configuring the grouped-object storage system to have RAID level 6 protection.

16. The method according to claim 11, further comprising storing the physical objects on a plurality of object storage devices.

17. The method according to claim 16, wherein at least one object storage device is a tape drive.

18. The method according to claim 16, wherein at least one object storage device is a random access memory device.

19. The method according to claim 16, wherein at least one object storage device is an optical storage drive.

20. The method according to claim 16, wherein at least one object storage device is a hard disk drive.