Areca ARC-1110, ARC-1130, ARC-1231ML/1261ML/1280ML, ARC-1120 manual Introduction

INTRODUCTION

the array. The parity data created during the exclusive-or is then written to the last drive in the array. If a single drive fails, data is still available by computing the exclusive-or of the contents cor- responding strips of the surviving member disk. RAID 3 is best for applications that require very fast data- transfer rates or long data blocks.

1.7.5 RAID 5

RAID 5 is sometimes called striping with parity at byte level. In RAID 5, the parity information is written to all of the drives in the controllers rather than being concentrated on a dedicated parity disk. If one drive in the system fails, the parity information can be used to reconstruct the data from that drive. All drives in the array system can be used for seek operations at the same time, greatly increasing the performance of the RAID system. This relieves the write bottleneck that characterizes RAID 4, and is the primary reason that RAID 5 is more often implemented in RAID arrays.

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