MHPR: Multi-head Parallelism and Redundancy Disk Model

Abstract

Performance and reliability are eternal topics in storage system. Nowadays, vast majority of storage system are made up of hard disk drive. The performance and reliability of hard disk drive are very important subclass of the former. So far, most researches of hard disk drive are single benefit. Some improve performance and some enhance the reliability. It is very little production which can heighten both performance and reliability at the same time. A new disk model we present fills this blank. The model not only improves disk drive performance, but also enhances reliability. The model is called MHPR (multi-head parallelism and redundancy). The models add more heads in one arm assembly, introduce redundancy and parallelism into disk. We analyze the performance and reliability in theory, and use different traces to evaluate the model in a simulator. We find that MHPR model can reduce seek time and transfer time effectively. The access time of single request is reduced. The model greatly shortens the queue time of single request in the case of two traces. So, the response of request is much faster; Response time of single disk drive is reduced by 98% and 80%, respectively in heavy workload and light workload. Using MHPR model to build RAID array, the MTTDL of this storage system can be improved 2-43 times.

Analysis of Traditional Hard Disk Scheduling Algorithms: A Review

“…A new disk model MHPR (Multi-head Parallelism and Redundancy), represented by Yang [14], reduced the access time of a single I/O request and increased the response time. In [6], the authors inspired by [14], proposed optimized disk scheduling based on two heads disk.…”

“…A new disk model MHPR (Multi-head Parallelism and Redundancy), represented by Yang [14], reduced the access time of a single I/O request and increased the response time. In [6], the authors inspired by [14], proposed optimized disk scheduling based on two heads disk. As the name suggests, the first disk head is at the position of track number zero (0), named as "HL," which moves from left to right.…”