Apparatus, system, and method for destaging cached data
First Claim
1. A method for satisfying storage requests while destaging cached data, the method comprising:
- sampling a destage rate for a nonvolatile solid-state cache, a total cache write rate for the cache, and a dirtied data rate, the destage rate comprising a rate at which dirty data is destaged from the cache, the total cache write rate comprising a total amount of data written to the cache in response to user write requests, the total cache write rate further comprising a dirty write hit rate and a clean write hit rate, the dirty write hit rate comprising a rate at which cache writes invalidate dirty data in the cache, the clean write hit rate comprising a rate at which cache writes invalidate previously destaged clean data in the cache, the dirtied data rate comprising a rate at which write operations increase an amount of dirty data in the cache;
determining a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio, the destage write ratio comprising a predetermined ratio between the dirtied data rate and the destage rate; and
enforcing the target cache write rate such that the total cache write rate satisfies the target cache write rate.
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Accused Products
Abstract
An apparatus, system, and method are disclosed for satisfying storage requests while destaging cached data. A monitor module samples a destage rate for a nonvolatile solid-state cache, a total cache write rate for the cache, and a dirtied data rate. The dirtied data rate comprises a rate at which write operations increase an amount of dirty data in the cache. A target module determines a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio. The destage write ratio comprises a predetermined ratio between the dirtied data rate and the destage rate. A rate enforcement module enforces the target cache write rate such that the total cache write rate satisfies the target cache write rate.
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Citations
20 Claims
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1. A method for satisfying storage requests while destaging cached data, the method comprising:
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sampling a destage rate for a nonvolatile solid-state cache, a total cache write rate for the cache, and a dirtied data rate, the destage rate comprising a rate at which dirty data is destaged from the cache, the total cache write rate comprising a total amount of data written to the cache in response to user write requests, the total cache write rate further comprising a dirty write hit rate and a clean write hit rate, the dirty write hit rate comprising a rate at which cache writes invalidate dirty data in the cache, the clean write hit rate comprising a rate at which cache writes invalidate previously destaged clean data in the cache, the dirtied data rate comprising a rate at which write operations increase an amount of dirty data in the cache; determining a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio, the destage write ratio comprising a predetermined ratio between the dirtied data rate and the destage rate; and enforcing the target cache write rate such that the total cache write rate satisfies the target cache write rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for satisfying storage requests while destaging cached data, the apparatus comprising:
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a monitor module that samples a destage rate for a nonvolatile solid-state cache, a total cache write rate for the cache, and a dirtied data rate, the destage rate comprising a rate at which dirty data is destaged from the cache, the total cache write rate comprising a total amount of data written to the cache in response to user write requests, the total cache write rate further comprising a dirty write hit rate and a clean write hit rate, the dirty write hit rate comprising a rate at which cache writes invalidate dirty data in the cache, the clean write hit rate comprising a rate at which cache writes invalidate previously destaged clean data in the cache, the dirtied data rate comprising a rate at which write operations increase an amount of dirty data in the cache; a target module that determines a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio, the destage write ratio comprising a predetermined ratio between the dirtied data rate and the destage rate; and a rate enforcement module that enforces the target cache write rate such that the total cache write rate satisfies the target cache write rate. - View Dependent Claims (18)
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19. A system for satisfying storage requests while destaging cached data, the system comprising:
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a nonvolatile solid-state cache; a backing store for the nonvolatile solid-state cache; a cache controller for the nonvolatile solid-state cache, the cache controller comprising, a monitor module that samples a destage rate from the cache to the backing store, a total cache write rate for the cache, and a dirtied data rate, the destage rate comprising a rate at which dirty data is destaged from the cache, the total cache write rate comprising a total amount of data written to the cache in response to user write requests, the total cache write rate further comprising a dirty write hit rate and a clean write hit rate, the dirty write hit rate comprising a rate at which cache writes invalidate dirty data in the cache, the clean write hit rate comprising a rate at which cache writes invalidate previously destaged clean data in the cache, the dirtied data rate comprising a rate at which write operations increase an amount of dirty data in the cache; a target module that determines a target cache write rate for the cache based on the destage rate, the total cache write rate, and the dirtied data rate to target a destage write ratio, the destage write ratio comprising a predetermined ratio between the dirtied data rate and the destage rate; and a rate enforcement module that enforces the target cache write rate such that the total cache write rate satisfies the target cache write rate. - View Dependent Claims (20)
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Specification