US 2015/0317090 A1Published application

System and Method of Life Management for Low Endurance SSD NAND Devices Used as Secondary Cache

AssigneeLSI Corporation

InventorsSumanesh Samanta, Mohana Rao Goli, Karimulla Sheik

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Abstract

A system and method for managing the life expectancy of at least one solid state drive (SSD) within a cache device of a storage subsystem includes determining a baseline rate of decline for each SSD based on its guaranteed life expectancy. At intervals, each SSD of the cache device is polled for remaining life and power-on time, and a current rate of decline (based on time since initialization) and a cumulative rate of decline (based on total lifespan of the SSD) is determined. When both the current rate of decline and the cumulative rate of decline exceed the baseline rate of decline for any SSD of the cache device, write requests to that SSD are blocked and redirected to the virtual device until either the current rate of decline or cumulative rate of decline drop below the baseline rate.

Claims19

Dependent claims

A method for managing the life expectancy of at least one solid state drive (SSD) in a storage subsystem, comprising:

initializing at least one cache device including the at least one SSD;
determining a first rate of change representing a relationship between the rated life expectancy of the at least one SSD and the chronological lifespan of the at least one SSD;
determining a first parameter associated with the remaining life of the at least one SSD;
determining a second parameter associated with the power-on time of the at least one SSD;
starting at least one timer to run for a predetermined interval,
when the at least one timer expires, determining a third parameter associated with the remaining life of the at least one SSD, determining a fourth parameter associated with power-on time of the at least one SSD after initializing the at least one cache device, and restarting the at least one timer;
determining a second rate of change representing a relationship between life expended by the at least one SSD after initializing the at least one cache device and power-on time of the at least one SSD after initializing the at least one cache device;
determining a third rate of change representing a relationship between total life expended by the at least one SSD and total power-on time of the at least SSD;
and
when both the second rate of change and the third rate of change are greater than the first rate of change:
blocking at least one I/O request to the at least one SSD, and
redirecting the at least one I/O request to at least one of a back-end disk and a virtual device.

9 more elements

A system for managing the life expectancy of at least one solid state drive (SSD) in a storage subsystem, comprising:

at least one cache device incorporating the at least one SSD;
at least one of a back-end disk and a virtual device;
at least one timer configured to run for a predetermined interval;
and
a firmware level operably coupled to the at least one SSD and configured to
(a) initialize the at least one cache device;
(b) start the at least one timer;
(c) determine a first rate of change representing a relationship between the rated life expectancy of the at least one SSD and the chronological lifespan of the at least one SSD;
(d) determine a first parameter associated with the remaining life of the at least one SSD at the time of initialization;
(e) determine a second parameter associated with the power-on time of the at least one SSD at the time of initialization;
(f) when the at least one timer expires, receive a third parameter associated with the remaining life of the at least one SSD, receive a fourth parameter associated with power-on time of the at least one SSD after initializing the at least one cache device, and restart the at least one timer;
(g) determine a second rate of change representing a relationship between life expended by the at least one SSD after initializing the at least one cache device and power-on time of the at least one SSD after initializing the at least one cache device;
(h) determine a third rate of change representing a relationship between total life expended by the at least one SSD and total power-on time of the at least SSD;
and
(i) when both the second rate of change and the third rate of change are greater than the first rate of change:
Nock at least one I/O request to the at least one SSD, and redirect the at least one I/O request to at least one of a back-end disk and a virtual device.

13 more elements

A data storage subsystem including a system for managing the life expectancy of at least one solid state drive (SSD) in a storage subsystem, comprising:

at least one cache device incorporating the at least one SSD;
at least one of a back-end disk and a virtual device;
at least one timer configured to run for a predetermined interval;
and
a firmware level operably coupled to the at least one SSD and configured to
(a) initialize the at least one cache device;
(b) start the at least one timer;
(c) determine a first rate of change representing a relationship between the rated life expectancy of the at least one SSD and the chronological lifespan of the at least one SSD;
(d) determine a first parameter associated with the remaining life of the at least one SSD at the time of initialization;
(e) determine a second parameter associated with the power-on time of the at least one SSD at the time of initialization;
(f) when the at least one timer expires, determine a third parameter associated with the remaining life of the at least one SSD, determine a fourth parameter associated with power-on time of the at least one SSD after initializing the at least one cache device, and restart the at least one timer;
(g) determine a second rate of change representing a relationship between life expended by the at least one SSD after initializing the at least one cache device and power-on time of the at least one SSD after initializing the at least one cache device;
(h) determine a third rate of change representing a relationship between total life expended by the at least one SSD and total power-on time of the at least SSD;
and
(i) when both the second rate of change and the third rate of change are greater than the first rate of change:
block at least one I/O request intended for the at least one SSD, and redirect the at least one I/O request to at least one of a back-end disk and a virtual device;
and
(j) when either the second rate of change or the third rate of change is not greater than the first rate of change, resume receipt of the at least one I/O request via the at least one SSD.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/268,591Filed 2 May 2014
Published: 5 Nov 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

G06F 3/0616
Improving the reliability of storage systems: in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
G06F 3/06
Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for…: digital…
G06F 3/0635
Configuration or reconfiguration of storage systems: by changing the path, e.g. traffic rerouting, path reconfiguration
G06F 3/0653
Making use of a particular technique: monitoring storage devices or systems