Patent ID: 8140811

Claim:
A method for facilitating data transfer between a nonvolatile storage (NVS) write cache and a pool of target storage devices by a processor, comprising: determining each target storage device in the pool of target storage devices as one of a hard disk drive (HDD) and a solid state drive (SSD) device, the each target storage device classified into one of a SSD rank group and a HDD rank group in the pool of target storage devices; wherein if no data is received in the NVS write cache for a predetermined time to be written to a target storage device classified in the SSD rank group: setting a threshold of available space in the NVS write cache to allocate at least a majority of the available space to the HDD rank group, and upon receipt of a write request for the SSD rank group, reducing the threshold of the available space in the NVS write cache to allocate a greater portion of the available space to the SSD rank group.