Best Configuration for Full Fault Tolerance with Seven SCSI Drives

D.

The BEST configuration when using seven SCSI drives in order to have full fault tolerance would be RAID 6.

RAID stands for Redundant Array of Independent Disks, and it is a technology used to increase storage performance, capacity, and data redundancy. There are different types of RAID configurations, each with its own advantages and disadvantages.

RAID 0+1 is a combination of RAID 0 and RAID 1, where data is first striped across multiple disks in RAID 0 configuration, and then mirrored to another set of disks in RAID 1 configuration. This provides high performance and fault tolerance, but requires at least four disks. In this scenario, with seven disks available, RAID 0+1 would not provide full fault tolerance as it can tolerate only a single disk failure in each set.

RAID 0 is a configuration where data is striped across multiple disks, providing high performance and capacity but no fault tolerance. Therefore, this option is not suitable for this scenario as it provides no data redundancy.

RAID 1 is a configuration where data is mirrored across two disks, providing full fault tolerance but lower capacity and performance. In this case, RAID 1 would require at least four disks to provide full fault tolerance, so it would not be the best configuration with only seven disks available.

RAID 5 is a configuration where data is striped across multiple disks, and parity information is stored on a separate disk, providing fault tolerance and higher capacity than RAID 1. However, RAID 5 can tolerate only one disk failure, which means that with seven disks, there would be a risk of data loss if more than one disk fails simultaneously.

Therefore, the BEST configuration for using seven SCSI drives in order to have full fault tolerance would be RAID 6. RAID 6 is similar to RAID 5, but it stores two sets of parity information across multiple disks, which allows it to tolerate up to two disk failures without data loss. RAID 6 provides full fault tolerance with seven disks, while still offering higher capacity and performance than RAID 1.