I/O Scheduling Algorithm for Data Servers in Cloud Storage Environments

Distributed file systems (DFSs) are generally employed for storing user data while designing a cloud storage system. The primary aspects of DFSs include efficient storage and management of metadata, data distribution strategies, and reliability of user data. In the case of data servers of a DFS, the FIFO (first in first out) strategy is adopted for scheduling I/O requests which are received by a data server daemon. The FIFO algorithm prioritises all such requests equally; requests that require better quality of services may therefore be blocked for long durations. To address this issue, a new priority based periodic scheduling algorithm (PPSA) has been proposed. Initially, PPSA classifies requests into different priority queues. Then, it periodically schedules requests according to their respective priorities and dedicated time slices. The obtained DFS simulation results show that PPSA can increase the response performance of heavy-load real-time requests by 20%, and can also ascertain the lowest response time performance for other requests.