Flash memory scrub management

Patent metadata

Field	Value
Publication number	US-9727413-B2
Application number	US-201313929853-A
Country	US
Kind code	B2
Filing date	Jun 28, 2013
Priority date	Jun 28, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A method, computer-readable storage media, and a system are provided for managing a scrub. The method may include detecting a trigger for the scrub. The trigger may be based upon a metric of a memory unit. The method may further include scrubbing the memory unit based upon the detection of the trigger.

First claim

What is claimed is:

1. A method for managing memory scrubbing in a flash memory unit, the method comprising:
detecting, using a first sensor external to a flash controller communicatively connected to a flash memory unit, a first temperature metric for the flash memory unit;
detecting, using a second sensor internal to the flash controller, a first access rate metric for the flash memory unit;
determining a trigger, the trigger based on temperature and access rate for the flash memory unit;
detecting, based on the first temperature metric and the first access rate metric, that the trigger has been achieved; and
write scrubbing the flash memory unit in response to detecting that the trigger has been achieved by writing new data to the flash memory unit, and then reading and error checking the data from the flash memory unit.

2. The method of claim 1 , further comprising:
delaying the write scrubbing of the flash memory unit based upon the availability of system resources required for the write scrubbing.

3. The method of claim 1 , wherein the flash memory unit is selected as one or more of a group consisting of a memory block, a memory page, and a memory sector.

4. The method of claim 1 , further comprising:
detecting, using the second sensor, an error history metric for the flash memory unit;
wherein the trigger is further based on the error history metric.

5. The method of claim 1 , further comprising:
detecting, using the first sensor, a second temperature metric for the flash memory unit;
detecting, using the second sensor, a second access rate metric for the flash memory unit;
detecting, based on the second temperature metric and the second access rate metric, that the trigger has been achieved; and
read scrubbing the flash memory unit in response to detecting that the trigger has been achieved.

6. A computer program product for managing memory scrubbing in a flash memory unit, the computer program product comprising a 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:
detecting, using a first sensor external to a flash controller communicatively connected to a flash memory unit, a first temperature metric for the flash memory unit;
detecting, using a second sensor internal to the flash controller, a first access rate metric for the flash memory unit;
determining a trigger, the trigger based on temperature and access rate for the flash memory unit;
detecting, based on the first temperature metric and the first access rate metric, that the trigger has been achieved; and
write scrubbing the flash memory unit in response to detecting the trigger by writing new data to the flash memory unit, and then reading and error checking the data from the flash memory unit.

7. The computer program product of claim 6 , wherein the program instructions executable by the computer cause the computer to perform the method further comprising:
delaying the write scrubbing of the flash memory unit based upon the availability of system resources required for the write scrubbing.

8. The computer program product of claim 6 , wherein the flash memory unit is selected as one or more of a group consisting of a memory block, a memory page, and a memory sector.

9. The computer program product of claim 6 , wherein the program instructions executable by the computer cause the computer to perform the method further comprising:
detecting, using the second sensor, an error history metric for the flash memory unit;
wherein the trigger is further based on the error history metric.

10. The computer program product of claim 6 , wherein the program instructions executable by the computer cause the computer to perform the method further comprising:
detecting, using the first sensor, a second temperature metric for the flash memory unit;
detecting, using the second sensor, a second access rate metric for the flash memory unit;
detecting, based on the second temperature metric and the second access rate metric, that the trigger has been achieved; and
read scrubbing the flash memory unit in response to detecting that the trigger has been achieved.

11. A system comprising:
a flash memory unit;
a first sensor configured to:
sense a first temperature metric for the flash memory unit; and
a flash memory controller, in communication with the flash memory unit, the flash memory controller configured to:
detect a first access rate metric for the flash memory unit;
determine a trigger, the trigger based on temperature and access rate for the flash memory unit;
detect, using the first temperature metric and the first access rate metric, that the trigger has been achieved; and
write scrub the flash memory unit in response to detecting that the trigger has been achieved by writing new data to the flash memory unit, and then reading and error checking the data from the flash memory unit.

12. The system of claim 11 , wherein the flash memory controller is further configured to:
detect an error history metric;
wherein the trigger is further based on the error history metric.

13. The system of claim 11 , wherein the flash memory unit is selected as one or more from a group consisting of a memory block, a memory page, and a memory sector.

14. The system of claim 11 , wherein:
the first sensor is further configured to:
sense a second temperature metric for the flash memory unit; and
wherein the flash memory controller is further configured to:
detect a second access rate metric for the flash memory unit;
detect, using the second temperature metric and the second access rate metric, that the trigger has been achieved; and
read scrub the flash memory unit in response to detecting that the trigger has been achieved.

Assignees

• IBM

Inventors

• Cordero Edgar R
• Tressler Gary A
• Vidyapoornachary Diyanesh B

Classifications

• G06F11/106 Primary

  Correcting systematically all correctable errors, i.e. scrubbing · CPC title