Automated Storage Management with QoS Guarantee in Large-scale Virtualized Storage Systems.

Traditionally storage has been purchased and attached to a single computer system. Such storage is accessible only through the computer system to which it is locally attached. In the last 10 years, especially in corporate data centers, storage is being increasingly purchased independent of the processors, and independently managed and administered. Because of the standardization of disk IO protocols, storage can be easily shared amongst various heterogeneous processors running various applications. The shared storage is accessed over a network interconnecting the processors to the shared disk subsystem, known as the storage area network a network onwhich processors send IO calls to virtual disks. It is the task of the storage controller to manage the mapping of virtual disks to physical disks, a task known as storage virtualization, similar to memory virtualization of processors. The storage virtualization layer has been exploited to provide diverse storage functions.