DYNAMIC SPARE STORAGE ALLOCATION

• US 20170315745A1
• Filed: 04/27/2016
• Published: 11/02/2017
• Est. Priority Date: 04/27/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Agombar, John P., Boden, Ian, Hutchison, Gordon D., Sanders, Lee J.
• Granted Patent: US 10,635,344 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A storage drive array with available storage space for user data with storage capacity in the array allocated to distributed spare space. The distributed spare space spreads portions of a spare drive across multiple storage drives in the array. By monitoring the amount of spare space available in the array, a determination may be whether the amount of spare space falls below a threshold number of drives. If there is un-used space in the available storage space which is greater than one drive of space, a drive of space to spare space may be dynamically re-allocated in a distributed pattern across the drives of the array.

Claims

1. A computer-implemented method for dynamic spare storage allocation, comprising:

providing a storage array with available storage space for user data, the storage array comprising one or more member drives;

allocating an amount of storage space in the array to distributed spare space, wherein distributed spare space spreads portions of each spare drive across multiple storage drives in the array;

monitoring the amount of spare space available in the array;

determining the amount of spare space falls below a threshold number of drives of spare space;

determining there is un-used space in the available storage space which is greater than one drive of space; and

dynamically re-allocating a new drive of space to spare space in a distributed pattern across the member drives of the array.

2. The method of claim 1, further comprising:

migrating user data in re-allocated areas of the drives of the array to new locations.

3. The method of claim 1, wherein determining there is un-used space in the available storage space which is greater than one drive of space includes determining the array'"'"'s actual size minus the used space is greater than the size of one member drive.

4. The method of claim 1, wherein monitoring the amount of spare space available in an array monitors when a spare drive is used up in an array such that the amount of spare space available falls below a threshold minimum number of spare drives.

5. The method of claim 1, further comprising:

adding the new drive of distributed spare space into data structures that describe the available distributed spare space.

6. The method of claim 1, wherein the threshold number of drives of spare space is two drives of space.

7. The method of claim 1, wherein dynamically re-allocating a drive of space to spare space in a distributed pattern across the drives of the array includes re-allocating areas, in a last area of space in each drive, of a size of one member drive divided by the number of drives in the array.

8. The method of claim 7, further comprising:

migrating, for every area including user data that is in an area that is being re-allocated by the array, the user data to free areas that are all below the area being re-allocated.

9. The method of claim 1, further comprising:

receiving notification from the array of a new maximum allowed logical block address in a drive in the form of the array'"'"'s previous maximum allowed logical block address less the size of a member drive divided by the number of drives in the array.

10. The method of claim 1, further comprising:

receiving notification from the array of a new array size in the form of the array'"'"'s previous size less the size of a member drive.

11. The method of claim 1, further comprising:

receiving notification from the array of designated logical block addresses greater than a new maximum allowed logical block address being new distributed spare space.

12. The method of claim 1, wherein the method is provided as a service in a cloud environment.

13. A system for dynamic spare storage allocation, including a storage controller having a processor and a memory configured to provide computer program instructions to the processor to execute the function of the following components, the storage controller comprising:

a configuration component for providing a storage array with available storage space for user data and an amount of storage capacity in the array allocated to distributed spare space, wherein distributed spare space spreads portions of each spare drive across one or more member drives in the array;

a spare capacity monitoring component for monitoring the amount of spare space available in an array and a spare threshold component for determining if the amount falls below a threshold number of drives of spare space;

an un-used space determining component for determining if there is un-used space in the available storage space which is greater than one drive of space; and

a re-allocating component for dynamically re-allocating a new drive of space to spare space in a distributed pattern across the drives of the array.

14. The system of claim 13, further comprising:

a migrating component for migrating user data in re-allocated areas of the drives of the array to new locations.

15. The system of claim 13, wherein the spare capacity monitoring component for monitoring the amount of spare space available in an array monitors when a spare drive is used up in an array such that the amount of spare space available falls below a threshold minimum number of spare drives.

16. The system of claim 13, further comprising:

a mapping component for adding the new drive of distributed spare space into data structures that describe the available distributed spare space.

17. The system of claim 13, wherein the re-allocating component for dynamically re-allocating a drive of space to spare space in a distributed pattern across the drives of the array comprises re-allocating areas in a last area of space in each drive of a size of the member drive divided by the number of drives in the array.

18. The system of claim 17, wherein for every area including user data that is in an area re-allocated by the array, the user data is migrated to free areas that are all below the area being re-allocated by the array.

19. The system of claim 13, further comprising:

an array communication component for receiving notification from the array of;

a new maximum allowed logical block address in a drive in the form of the array'"'"'s previous maximum allowed logical block address less the size of a member drive divided by the number of drives in the array;

a new array size in the form of the array'"'"'s previous size less the size of a member drive; and

any designated logical block addresses greater than the new maximum allowed logical block address being new distributed spare space.

20. A computer program product for dynamic spare storage allocation, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to:

provide a storage drive array with available storage space for user data;

allocate an amount of storage capacity in the array to distributed spare space, wherein distributed spare space spreads portions of each spare drive across multiple storage drives in an array;

monitor the amount of spare space available in an array and determining if the amount falls below a threshold number of drives of spare space;

determine if there is un-used space in the available storage space which is greater than one drive of space; and

dynamically re-allocate a drive of space to spare space in a distributed pattern across the drives of the array.