There are two common ways to implement RAID on your PC or server. They are called RAID 1 and RAID 5.
RAID 1:
RAID 1 is sometimes called “mirroring”. It is more commonly used on PCs than servers. The drives that you have are split into two equal groups. Your data is written to both halves of your hard drive storage at the same time. In other words, you have an immediate copy of your data in two separate (and equal) locations.
The only down side to RAID 1 is that your overall data storage on your server or PC is cut in half. However, your data is well protected. If either of your data storage locations suffers a non-recoverable problem, you just replace the damaged storage and the system will rebuild the “mirror”.
RAID 5:
RAID 5 is sometimes called “striping with parity”. It is more commonly used on servers. It requires that you have 3 or more identical drives that are set up into a storage array. Data is written across all but one of the drives. The last drive contains parity (or checksum) information.
To explain how RAID 5 works, let’s consider a simple storage array of 3 drives. We’ll call the drives A, B and C. In our simple example, data is written in stripes on drives A and B and drive C contains the parity information. Like a simple Algebra equation, the parity information works in a way that is analogous to A + B = C. If any of the drives is damaged, it can be replaced and the system can restore the information that was missing from the array based on how the parity information is calculated.
Notes:
- I have deliberately simplified how the RAID systems are actually implemented. However, you should be able to see how both systems help to make your data safer.
- Although implementing a RAID increases the safety of your data, it is not a replacement for backups. Remember to backup your data regularly!
