protoRAID: A user-level RAID emulator for fast prototyping in fibre channel SAN environment

Abstract

To measure accurate performance of the new RAID storage system, simulators and emulators must consider the behavior of system components, such as the host connection interface, internal system bus, internal I/O bus, and physical disk. Moreover, the behavior of RAID functional operations with the buffer cache is also considered important. Although many RAID simulators exist, they do not consider all the components of RAID storage systems, resulting in inaccurate performance measurements. As far as we know, there exists no RAID emulator that considers all system components. Therefore, we present a RAID emulator to correct this defect. It is implemented as a user-level process in Linux. It interacts with a host via a physical I/O interface like FibreChannel; that is, the effect of interactions between the host and the RAID controller is physically considered. It interacts with physical disks via SCSI or FibreChannel; that is, the effect of interaction between RAID controller and disks is considered. Moreover, RAID functional operations such as the buffer cache and block mapping function are also considered in overall timing measurements.