Managing storage devices having a lifetime of a finite number of operations

• US 10,394,463 B2
• Filed: 05/22/2017
• Issued: 08/27/2019
• Est. Priority Date: 05/20/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hutchison, Gordon D., Parkes, Jonathan M., Rogers, Nolan, Smith, Bruce J.
• Primary Examiner(s): Mackall, Larry T
• Application Number:
  US15/601,900
• Publication Number:
  US 20170255400A1
• Time in Patent Office: 827 Days
• Field of Search: 711103, 711154, 711159, 711160, 712 14, 712225, 712248
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7204 Capacity control, e.g. partitioning, end-of-life degradation
• CPC Class Codes: G06F 2212/7211 Wear leveling
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

Disclosed are methods and systems of managing a plurality of storage devices having a lifetime of a finite number of operations. An average number of storage devices reaching said lifetime of a finite number of operations per first unit time is calculated. For each one of the plurality of storage devices an estimated date when a finite number of operations will be reached is calculated. For each date, a variable related to the number of storage devices reaching said finite number of operations within a predetermined period of said date is set. For one or more variables having a value larger than average number of storage devices reaching said lifetime of a finite number of operations per first unit time, an action is carried out to reduce the number of storage devices reaching said lifetime per first unit of time.

Claims

1. A computer-implemented method of managing a plurality of storage devices, the storage devices having a lifetime of a finite number of operations, the method comprising:

calculating an average number of storage devices reaching said lifetime of a finite number of operations per first unit time;

for each one of the plurality of storage devices calculating an estimated date when said finite number of operations will be reached;

for each date, setting a variable associated with that date, the variable being related to a number of storage devices reaching said finite number of operations within a predetermined period of said date; and

for one or more variables associated with a date where the value of the variable is larger than the average number of storage devices reaching said lifetime of a finite number of operations per first unit time, carrying out an action to reduce the number of storage devices reaching said lifetime per first unit of time.

2. The method of claim 1, comprising allocating each one of the plurality of storage devices to one of a plurality of usage tiers, according to how many operations per second unit of time will be executed by each one of the plurality of storage devices;

and

wherein said action to reduce the number of operations per first unit of time is to exchange a storage device allocated to a usage tier having a larger number of operations per second unit of time with a storage device allocated to a usage tier having a smaller number of operations per second unit of time.

3. The method of claim 2, wherein said step of for one or more variables associated with a date where the value of the variable is larger than the average number of storage devices reaching said lifetime of a finite number of operations per first unit time comprises:

selecting the date which has the highest value of the variable associated with it;

selecting a first storage device with retiral date closest to the selected date;

if the retiral date is one of before or after the selected date, then identifying any second storage device reaching a retiral date within said predetermined period of said selected date, but one of respectively after or before said selected date;

if an exchange of said first and second storage devices and their respective tiers would result in a planned retiral date being outside the predetermined period of said selected date, then identifying the exchange as a potential exchange;

repeating said identifying steps until all first storage devices have been considered as potential exchanges; and

selecting one or more potential exchanges for implementation.

4. The method of claim 1, wherein said action is one or more of (i) to store more parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to store less parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

5. The method of claim 1 wherein said action is one or more of (i) to migrate extents having a higher number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to migrate extents having a lower number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

6. The method of claim 1, wherein said variable associated with said date is related to the average number of storage devices reaching said finite number of operations within said predetermined period of said date by weighting the number of storage devices reaching said finite number of operations by the time difference between said date and the estimated date when said finite number of operations will be reached.

7. The method of claim 1, wherein said storage devices have a lifetime of a finite number of write operations.

8. A system for managing a plurality of storage devices, the storage devices having a lifetime of a finite number of operations, the system comprising:

an input/output adapter for receiving requests for data transfers to and/or from the plurality of storage devices;

a storage device interface for performing said requests for data transfers to and/or from the plurality of storage devices; and

a storage device lifetime management unit for managing said storage devices so as to optimize the number of storage devices reaching said lifetime per first unit of time;

wherein;

said storage device lifetime management unit is configured to calculate an average number of storage devices reaching said lifetime of a finite number of operations per first unit time;

said storage device lifetime management unit is configured to calculate an estimated date when said finite number of operations will be reached for each one of the plurality of storage devices;

said storage device lifetime management unit sets a variable associated with each date, the variable being related to a number of storage devices reaching said finite number of operations within a predetermined period of said date;

for one or more variables associated with a date where the value of the variable is larger than the average number of storage devices reaching said lifetime of a finite number of operations per first unit time, said storage device lifetime management unit is configured to carry out an action to reduce the number of storage devices reaching said lifetime per first unit of time.

9. The system of claim 8, wherein:

said storage device lifetime management unit allocates each one of the plurality of storage devices to one of a plurality of usage tiers, according to how many operations per second unit of time will be executed by each one of the plurality of storage devices; and

said action carried out by said storage device lifetime management unit is to reduce the number of operations per first unit of time is to exchange a storage device allocated to a usage tier having a larger number of operations per second unit of time with a storage device allocated to a usage tier having a smaller number of operations per second unit of time.

10. The system of claim 8, wherein said storage device lifetime management unit is configured to determine whether to carry out an action to reduce the number of storage devices reaching their lifetime per first unit of time by

said storage device lifetime management unit selecting the date which has the highest value of the variable associated with it;

said storage device lifetime management unit selecting a first storage device with retiral date closest to the selected date;

said storage device lifetime management unit determining if the retiral date is one of before or after the selected date, and identifying any second storage device reaching a retiral date within said predetermined period of said selected date, but one of respectively after or before said selected date;

said storage device lifetime management unit determining if an exchange of said first and second storage devices and their respective tiers would result in a planned retiral date being outside the predetermined period of said selected date, and responsive to said determination, identifying the exchange as a potential exchange;

said storage device lifetime management unit repeating said identifying until all first storage devices have been considered as potential exchanges; and

said storage device lifetime management unit selecting one or more potential exchanges for implementation.

11. The system of claim 8, wherein said action is one or more of (i) to store more parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to store less parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

12. The system of claim 8 wherein said action is one or more of (i) to migrate extents having a higher number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to migrate extents having a lower number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

13. The system of claim 8, wherein said variable associated with said date is related to the number of storage devices reaching said finite number of operations within said predetermined period of said date by weighting the number of storage devices reaching said finite number of operations by the time difference between said date and the estimated date when said finite number of operations will be reached.

14. The system of claim 8, wherein said storage devices have a lifetime of a finite number of write operations.

15. A computer program product for managing a plurality of storage devices, the storage devices having a lifetime of a finite number of operations, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising:

calculating, by the computer, an average number of storage devices reaching said lifetime of a finite number of operations per first unit time;

calculating, by the computer, an estimated date when said finite number of operations will be reached for each one of the plurality of storage devices;

for each date, setting, by the computer, a variable associated with that date, the variable being related to a number of storage devices reaching said finite number of operations within a predetermined period of said date; and

for one or more variables associated with a date where the value of the variable is larger than the average number of storage devices reaching said lifetime of a finite number of operations per first unit time, carrying out, by the computer, an action to reduce the number of storage devices reaching said lifetime per first unit of time.

16. The computer program product of claim 15, comprising program instructions executable by the computer to cause the computer to allocate each one of the plurality of storage devices to one of a plurality of usage tiers, according to how many operations per second unit of time will be executed by each one of the plurality of storage devices;

and

wherein said action to reduce the number of operations per first unit of time is to exchange a storage device allocated to a usage tier having a larger number of operations per second unit of time with a storage device allocated to a usage tier having a smaller number of operations per second unit of time.

17. The computer program product of claim 16, wherein said step of for one or more variables associated with a date where the value of the variable is larger than the average number of storage devices reaching said lifetime of a finite number of operations per first unit time comprises:

selecting the date which has the highest value of the variable associated with it;

selecting a first storage device with retiral date closest to the selected date;

if the retiral date is one of before or after the selected date, then identifying any second storage device reaching a retiral date within said predetermined period of said selected date, but one of respectively after or before said selected date;

if an exchange of said first and second storage devices and their respective tiers would result in a planned retiral date being outside the predetermined period of said selected date, then identifying the exchange as a potential exchange;

repeating said identifying steps until all first storage devices have been considered as potential exchanges; and

selecting one or more potential exchanges for implementation.

18. The computer program product of claim 15, wherein said action is one or more of (i) to store more parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to store less parity information on storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

19. The computer program product of claim 15, wherein said action is one or more of (i) to migrate extents having a higher number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but before said date;

or (ii) to migrate extents having a lower number of operations per unit time to storage drives reaching said lifetime of a finite number of operations within said predetermined period of said date, but after said date.

20. The computer program product of claim 15, wherein said variable associated with said date is related to the number of storage devices reaching said finite number of operations within said predetermined period of said date by weighting the number of storage devices reaching said finite number of operations by the time difference between said date and the estimated date when said finite number of operations will be reached.