Patent ID: 8930619
Filing Date: 2015-01-06
Classification: G06F

Abstract:
1. A method for efficiently destaging write data from a storage controller to storage devices, comprising: determining, by the storage controller, that a cache element should be transferred from a write cache of the storage controller to the storage devices, wherein cache elements are fixed size portions of the write cache; calculating, by the storage controller, that a dirty watermark is above a dirty watermark maximum value, wherein the dirty watermark identifies the amount of dirty data in the write cache, wherein dirty data is data in the write cache that has not yet been written to storage devices; identifying, by the storage controller, a first cache element to destage from the write cache to the storage devices; transferring, by the storage controller, a first data container comprising the first cache element from the write cache to the storage devices; incrementing, by the storage controller, an active destage count, wherein the active destage count is a current number of host write requests issued to a virtual disk that have not yet been completed, wherein the virtual disk is a RAID group comprising one or more specific storage devices; and repeating determining, calculating, identifying, transferring, and incrementing, by the storage controller, if the active destage count is less than an active destage count maximum value.