Definition of a RAID 5 Array
A RAID 5 array uses at least three disks and stripes information at the byte level across the member disks. Parity data is also written across each member disk to allow the RAID data to be recovered in the event of a disk failure.
Different Ways a RAID 5 Array Can Be Set Up
A RAID 5 array can be set up as a software RAID using special software or as a hardware RAID using a RAID controller.
A software RAID is generally either set up using standalone software or using RAID software which is built into an operating system such as Windows 2003 Server. A software RAID uses the CPU and memory of the computer on which it is installed. This can slow down other applications on that computer. This also makes the software RAID vulnerable to failure due to problems with the host computer. A hardware RAID uses a RAID controller which handles array duties thus there is no strain on the host computer's CPU and memory.
Applications Best Suited for RAID 5
Since RAID 5 offers better read performance than write performance, it is best suited for read-oriented applications such as web, intranet, and email servers. It could also be suited for databases as long as there is more reading than writing. With RAID 5, writes are slowed down because the array must write parity data to the disks.
Advantages and Disadvantages of RAID 5 Arrays
There are several advantages from a RAID 5 array. Since a RAID 5 writes parity data to each of the member disks, a RAID 5 can sustain the failure of one disk. The parity data allows the RAID to be recovered . Another advantage of RAID 5 is that it is fairly cost-effective considering the amount of fault tolerance it provides. Finally, RAID 5 offers a good rate of reads to the member disks. Some disadvantages of RAID 5 are that it offers slower writes as it must write parity data in addition to regular data. It can also be expensive to implement as it requires special hardware.
Conclusion
Overall, RAID 5 offers excellent fault tolerance without wasting drive space. It also offers a high read performance making it suitable for a wide variety of applications. More information about RAID 5 arrays can be found at RAID 5 Data Recovery.
