Exercises 2

Exercises 2

Introduction

The term RAID is an acronym of English "Redundant Array of Independent Disks", which means redundant array of independent disks. RAID is a method of combining several hard disks into a single logical unit in which data is stored redundantly. It provides greater fault tolerance and higher levels of performance than a single hard drive or a group of independent hard drives. RAID technology protects data against the failure of a hard drive. If a fault occurs, RAID keeps the server up and running until you replace the defective unit.

Discussion

RAID technology is also used frequently to improve the performance of servers and workstations. These two objectives, data protection and performance improvement are not mutually exclusive. RAID systems all involve loss of part of the storage capacity of the disks, to provide redundant or parity data store. RAID offers several options, called RAID levels, each of which provides a different balance between fault tolerance, performance and cost.

RAID Levels 

Choice of different RAID levels will depend on user requirements in terms of factors such as safety, speed, capacity, cost, etc. Each RAID level offers a specific combination of fault tolerance (redundancy), performance and cost, designed to meet different storage needs. Most RAID levels can be met effectively only one or two of these criteria.

RAID 0: Disk Striping "Highest transfer, but no fault tolerance"

It's Also known as "separation or fractionation / Striping". The data are broken down into small pieces and distributed across multiple drives. This level of "array" or matrix provides fault tolerance. With no redundancy, RAID 0 offers no data protection. Failure of any disc in the array would result in loss of data and would be necessary to restore from a backup. Therefore, RAID 0 does not really fit the acronym RAID. Is a series of disk drives connected in parallel to allow simultaneous transfer of data to all of them, thereby ...