RAID set-ups are software and hardware systems that are capable of writing or reading data to and from multiple hard drives, in a modern system different levels of RAID systems can be nested or joined to supply more data redundancy
& integrity or for a higher read/write speed, The level of a RAID is consistently indicated using a number from 0-6
for example RAID 0 or RAID 1 an example of a nested RAID would be RAID 1+0 the 1 represents a RAID 1 and the 0
represents a RAID 0.
When you are explaining the functions of a RAID level there are two phrases that are most commonly used these are; Striping & Mirroring, Striping is when a file is written to multiple drives in the exact same way this supplies a much faster write speed but doesn't supply any safety from redundancy in its simplest form. Mirroring is where files are written to two or more drives in the same manner this supplies a read speed when several users need the same data, it also provides defences against redundancy as the same data is on multiple drives.
What Is A RAID 5?
A RAID 5 uses striping to give fault tolerance in the event of disk failure plus it provides a better read speed, fault tolerance is accomplished through having data saved across the drives but with parity data saved as well, whether a hard drive breaks the lost data can be rebuilt using the parity data saved on the other drives. RAID 5 set-ups optimise storage capacity supplied by RAID's as there are no large amounts of data on one drive, a RAID 5 has certain advantages.
RAID 5 Benefits :
1. Optimise Storage use
2. Protection against disk failure
3. Quick read speed
The fast read speed makes this system ideal for data archiving systems and any company area which accesses certain information on an incredibly routine basis. However, write speed is declined compared to other RAID's, as the additional parity data must be written along with the core data. If your own company has data which is not modified on a regular basis, but at the same time is read by many users and systems, then RAID 5 is maybe an ideal solution for you. However, you do must be alert to potential system failures.
RAID 5 Failures
With a RAID 5 if one hard drive breaks then it is vital that the hard drive is replaced whenever possible because when the hard drive isn't replaced it causes harmful issues as it is expensive to have data recovered, if another hard drive breaks. When one hard drive breaks the system enters a critical state where write and read rate is reduced significantly but it's still possible to read and write to and from the hard drive. Bear in mind that RAID's aren't a back-up solution they are always there to supply fault tolerance.
A RAID 5 has some built in data redundancy protection and is capable of rapid read speeds; it is best designed for a business which depends on fast entry to data to reach your goals. Once a RAID 5 has been set up you will find a substantial increase in the read speed of your system.