A new destage algorithm for disk cache: DOME

Microprocessor technology is advancing at an incredible rate, unfortunately disk technology is not increasing at the same rate; thus, disk subsystem performance is becoming a dominant factor in the overall system behaviour. Disk caches have been effective to improve I/O performance. Several studies show that disk access patterns are dominated by write operations, then the use of non-volatile write caches together with a write-behind strategy seems to be essential. In this paper, a new destage algorithm for disk write caches, called DOME (Destage Only Modified oncE), is presented. Using simulation, DOME is compared with other preceding algorithms such as the threshold scheduling, providing better response time and behaviour, not only for write requests, but also for read requests. These results have been obtained feeding the simulator with real traces