A method for destaging write data from a storage controller to storage devices is provided. The method includes determining that a cache element should be transferred from a write cache of the storage controller to the storage devices, calculating that a dirty watermark is above a dirty watermark maximum value, identifying a first cache element to destage from the write cache to the storage devices, transferring a first data container including the first cache element to the storage devices, and incrementing an active destage count. The method also includes repeating determining, calculating, identifying, transferring, and incrementing if the active destage count is less than an active destage count maximum value. The active destage count is a current number of write requests issued to a virtual disk that have not yet been completed, and the virtual disk is a RAID group comprising one or more specific storage devices.