Dynamic overprovisioning for data storage systems
View Patent ↗Disclosed embodiments are directed to systems and methods for dynamic overprovisioning for data storage systems. In one embodiment, a data storage system can reserve a portion of memory, such as non-volatile solid-state memory, for overprovisioning. Depending on various overprovisioning factors, recovered storage space due to compressing user data can be allocated for storing user data and/or overprovisioning. Utilizing the disclosed dynamic overprovisioning systems and methods can result is more efficient utilization of cache memory, reduction of write amplification, increase in a cache hit rate, and the like. Improved data storage system performance and increased endurance and longevity can thereby be attained.
1. A data storage system comprising:
a non-volatile memory array comprising a user data portion and an overprovisioning portion, the user data portion configured to store user data;
a controller configured to dynamically adjust a capacity of the overprovisioning portion of the non-volatile memory array by:
compressing at least some user data stored in the user data portion;
determining an amount of recovered storage capacity due to the compression;
computing one or more overprovisioning parameters including a measure of an amount of non-redundant data stored in the non-volatile memory array, the non-redundant data comprising data that is not persistently stored in any memory of the data storage system other than the non-volatile memory array; and
allocating, based at least in part on the one or more overprovisioning parameters, the recovered storage capacity to at least one of a capacity of the user data portion and the capacity of the overprovisioning portion.
2. The data storage system of claim 1 , wherein the controller is configured to allocate the recovered storage capacity based at least in part on a combination of two or more of the one or more overprovisioning parameters.
3. The data storage system of claim 2 , wherein the controller is configured to determine a weighted average of the two or more overprovisioning parameters.
4. The data storage system of claim 1 , wherein the one or more overprovisioning parameters further include at least one of:
a user data compression rate;
the capacity of the overprovisioning portion;
a wear level of the non-volatile memory array;
a number of inoperative non-volatile memory array locations;
a ratio of an amount of data read from the non-volatile memory array to an amount of data written to the non-volatile memory array; and
a ratio of an amount of consecutive data written to the non-volatile memory array to an amount of non-consecutive data written to the non-volatile memory array.
5. The data storage system of claim 4 , wherein the controller is configured to allocate at least some of the recovered storage capacity to the capacity of the overprovisioning portion in response to at least one of:
an increase in the wear level of the non-volatile memory array as compared to a wear level threshold;
an increase in the ratio of the amount of data read from the non-volatile memory array to the amount of data written to the non-volatile memory array as compared to a read/write threshold; and
a decrease in the ratio of the amount of consecutive data written to the non-volatile memory array to the amount of non-consecutive data written to the non-volatile memory array as compared to a consecutive data written threshold.
6. The data storage system of claim 4 , wherein the controller is configured to allocate at least some of the recovered storage capacity to the capacity of the user data portion in response to at least one of:
an increase in the number of inoperative non-volatile memory locations as compared to an inoperative locations threshold;
a decrease in the user data compression rate as compared to a data compression threshold;
an increase in the capacity of the overprovisioning portion as compared to an overprovisioning threshold;
an increase in the ratio of the amount of consecutive data written to the non-volatile memory array to the amount of non-consecutive data written to the non-volatile memory array as compared to a consecutive data written threshold; and
an increase in the measure as compared to a non-redundant data threshold, the measure comprising a percentage of non-redundant data stored in the non-volatile memory array.
7. The data storage system of claim 1 , wherein the controller is configured to compress the at least some user data stored in the user data portion using lossless compression.
8. The data storage system of claim 1 , wherein the data storage system further comprises magnetic storage, and wherein the non-volatile memory array is configured as cache memory for the magnetic storage.
9. The data storage system of claim 8 , wherein the magnetic storage comprises shingled magnetic storage.
10. The data storage system of claim 1 , wherein the non-volatile memory array is configured as cache memory to a remote data storage.
11. In a data storage system comprising a non-volatile memory array comprising a user data portion and an overprovisioning portion, the user data portion configured to store user data, a method of dynamically adjusting a capacity of the overprovisioning portion, the method comprising:
compressing at least some user data stored in the user data portion;
determining an amount of recovered storage capacity due to the compression;
computing one or more overprovisioning parameters including a measure of an amount of non-redundant data stored in the non-volatile memory array, the non-redundant data comprising data that is not persistently stored in any memory of the data storage system other than the non-volatile memory array; and
allocating, based at least in part on the one or more overprovisioning parameters, the recovered storage capacity to at least one of a capacity of the user data portion and the capacity of the overprovisioning portion,
wherein the method is performed under control of a controller.
12. The method of claim 11 , wherein said allocating comprises allocating the recovered storage capacity based at least in part on a combination of each of the one or more overprovisioning parameters.
13. The method of claim 12 , wherein the combination comprises a weighted average of each of the one or more overprovisioning parameters.
14. The method of claim 11 , wherein the one or more overprovisioning parameters further include at least one of:
a user data compression rate;
the capacity of the overprovisioning portion;
a wear level of the non-volatile memory array;
a number of inoperative non-volatile memory array locations; and
a ratio of an amount of data read from the non-volatile memory array to an amount of data written to the non-volatile memory array, a ratio of an amount of consecutive data written to the non-volatile memory array to an amount of non-consecutive data written to the non-volatile memory array.
15. The method of claim 14 , wherein said allocating comprises allocating at least some of the recovered storage capacity to the capacity of the overprovisioning portion in response to at least two of:
an increase in the wear level of the non-volatile memory array as compared to a wear level threshold;
an increase in the ratio of the amount of data read from the non-volatile memory array to the amount of data written to the non-volatile memory array as compared to a read/write threshold; and
a decrease in the ratio of the amount of consecutive data written to the non-volatile memory array to the amount of non-consecutive data written to the non-volatile memory array as compared to a consecutive data written threshold.
16. The method of claim 14 , further comprising allocating at least some of the recovered storage capacity to the capacity of the user data portion in response to at least two of:
an increase in the number of inoperative non-volatile memory locations as compared to an inoperative locations threshold;
a decrease in the user data compression rate as compared to a data compression threshold;
an increase in the capacity of the overprovisioning portion as compared to an overprovisioning threshold;
an increase in the ratio of the amount of consecutive data written to the non-volatile memory array to the amount of non-consecutive data written to the non-volatile memory array as compared to a consecutive data written threshold; and
an increase in the measure as compared to a non-redundant data threshold, the measure comprising a percentage of non-redundant data stored in the non-volatile memory array.
17. The method of claim 11 , wherein said compressing the at least some user data stored in the user data portion comprises compressing using lossless compression.
18. The method of claim 11 , further comprises magnetic storage, and wherein the non-volatile memory array is configured as cache memory for the magnetic storage.
19. The method of claim 18 , wherein the magnetic storage comprises shingled magnetic storage module.
20. The method of claim 11 , wherein the non-volatile memory array is configured as cache memory to a remote data storage.