Patent ID: 8478945
Filing Date: 2013-07-02
Classification: G06F

Abstract:
1. A method of destaging data from a cache and respective portions of a non-volatile storage (NVS) via a device adapter to each of a plurality of storage devices, each said storage device having an associated current storage occupancy in the NVS, the method for destaging data from cache and the portion of the NVS to the associated storage device for each storage device comprising: adaptively varying a destage rate of data from cache to said storage device according to the current storage occupancy of the NVS associated with said storage device to set a nominal value for the destage rate so that on average the total occupancy of the NVS is maintained at approximately a desired occupancy to increase data throughput to the plurality of storage devices; checking a current stage activity on said storage device; adaptively adjusting the destage rate to said storage device from the nominal value according to the current stage activity on said storage device, said destage rate incremented if the current stage activity is less than a first threshold to empty the NVS aggressively when stage activity allows, to reduce host write times, and decremented if stage activity is greater than a second threshold to empty the NVS conservatively, when stage activity demands, to reduce host read times, while maintaining on average the total occupancy of the NVS at approximately the desired occupancy without sacrificing throughput; and destaging data from cache to said storage device at the adjusted destage rate for said storage device and discarding the destaged data from the portion of the NVS associated with said storage device.