Controlling wear among flash memory devices based on remaining warranty

Abstract

A method includes identifying a product warranty for each of a plurality of flash memory devices within a system, wherein the product warranty includes a maximum number of writes and a maximum age, and tracking the number of writes made to each flash memory device and the age of each flash memory device. The method further includes determining, for each flash memory device, a number of pro rata writes remaining in the product warranty, which is determined as a number of writes remaining until the flash memory device reaches the maximum number of writes identified in the product warranty divided by an amount of time remaining until the flash memory reaches the maximum age identified in the product warranty. The method then causes data to be written to the flash memory device having the greatest number of pro rata writes remaining in the product warranty.

What is claimed is: 
     
         1 . A method, comprising:
 identifying a product warranty for each of a plurality of flash memory devices within a system, wherein the product warranty includes a maximum number of writes and a maximum age;   tracking the number of writes made to each flash memory device and the age of each flash memory device;   determining, for each flash memory device, a number of pro rata writes remaining in the product warranty, wherein the number of pro rata writes remaining in the product warranty is determined as a number of writes remaining until the flash memory device reaches the maximum number of writes identified in the product warranty divided by an amount of time remaining until the flash memory reaches the maximum age identified in the product warranty; and   causing data to be written to the flash memory device having the greatest number of pro rata writes remaining in the product warranty.   
     
     
         2 . The method of  claim 1 , further comprising:
 identifying one of the flash memory devices having the least amount of time remaining until the flash memory reaches the product age identified in the product warranty; and   increasing a rate of writing data to the identified flash memory device so that the number of writes made to the identified flash memory device reaches the maximum number of writes identified in the product warranty at approximately the same time as the age of the identified flash memory device reaches the maximum age identified in the product warranty.   
     
     
         3 . The method of  claim 1 , wherein the flash memory is a component of a device selected from a solid state drive, a serial bus attached data storage device, and a flash memory module card. 
     
     
         4 . The method of  claim 1 , wherein the plurality of flash memory devices form a single logical memory device. 
     
     
         5 . The method of  claim 1 , wherein the plurality of flash memory devices are cache memory for a plurality of hard disk drives. 
     
     
         6 . The method of  claim 1 , wherein the step of determining, for each flash memory device, a number of pro rata writes remaining in the product warranty is performed by an operating system of a computer in communication with the plurality of flash memory devices. 
     
     
         7 . The method of  claim 1 , wherein the step of determining, for each flash memory device, a number of pro rata writes remaining in the product warranty is performed by an controller coupled to the plurality of flash memory devices. 
     
     
         8 . The method of  claim 1 , further comprising:
 wear leveling data stored on each flash memory device.   
     
     
         9 . The method of  claim 1 , wherein wear leveling data stored on each flash memory device is performed by a controller within each flash memory device.