This paper investigates the performance of redundant array of inexpensive disks (RAID) with a level of 5 by using a Markov model. Considering RAID systems cannot be adequately modeled using a single queuing model, we use four modes to model the RAID-5 system. The analytical model is verified by simulation through a Q+ simulation software package. The results obtained from the Markov model are v...

In this paper, we describe a design of a novel architecture for RAID that uses an SSD as a large cache to conserve energy. This approach stems from the fact that short term footprints are small enough to be efficiently managed within an SSD. More specifically, in this study, we consider two simple approaches to reduce the energy consumed in RAID. First, when a read happens in RAID, a copy of th...

Video servers must use large disk arrays to provide the huge amount of storage capacity and bandwidth needed. As the number of disk drives increases, the probability of a video server failure increases too. We propose a redundancy scheme that uses both RAID 5 techniques and mirroring to make a video server tolerant against all single disk failures. Our approach provides a unified framework for ...

We describe experimental results on large data transfers and stable control streams over a dedicated 1Gbps channel of several hundred miles length implemented over ORNLAtlanta production OC192 link. To support file transfers at 1Gbps rates, the end hosts are equipped with SCSI hard drives in a RAID 0 configuration and dedicated NICs, which are directly connected to the router. The 1Gbps channel...

As modern storage systems have grown in size and complexity, RAID-6 is poised to replace RAID-5 as the dominant form of RAID architectures due to its ability to protect against double disk failures. Many excellent erasure codes specially designed for RAID-6 have emerged in recent years. However, all of them have limitations. In this paper, we present a class of near perfect erasure codes for RA...

increases with more disks in the array (at a minimum, catastrophic data loss is twice as likely compared to single drives without RAID). A single disk failure destroys the entire array because when data is written to a RAID 0 volume, the data is broken into fragments called blocks. The number of blocks is dictated by the stripe size, which is a configuration parameter of the array. The blocks a...

We present a novel data organization for disk arrays|Segmented Information Dispersal (SID). SID provides protection against disk failures while ensuring that the reconstruction of the missing data requires only relatively small contiguous accesses to the available disks. SID has a number of properties that make it an attractive solution for fault-tolerant video servers. Under fault-free conditi...

This thesis studies the effects of latent sector faults on reliability, performance, and combined performability of disk arrays. This is done by developing two novel reliability models that include two fault types: disk unit faults and sector faults. The new reliability models study both hot swap and hot spare approaches in repairing disk unit faults. A traditional analytical method and also a ...

............................................................................................................................................. 2 Overview of the RAID 5 rebuild process ................................................................................................. 2 Estimating the mean-time-to-failure (MTTF) ..........................................................................

The effectiveness of the redundancy schemes that have been developed to enhance the reliability of storage systems has predominantly been evaluated based on the mean time to data loss (MTTDL) metric. This metric has been widely used to compare schemes, to assess tradeoffs, and to estimate the effect of various parameters on system reliability. Analytical expressions for MTTDL are typically deri...