A RAID is a data storage technology that takes multiple physical disk drive components into a single logical unit.
RAIDs are designed for two purposes: improved performance and data redundancy. There are several different RAID configurations that have both upsides and downsides so let's dive into the different RAIDs and which one is the best for performance and redundancy.
RAID 0 arrays include two or more disk drives and provide data striping. This means that data is evenly distributed across the disk drives in equally sized sections. The downside with RAID 0 arrays is that they do not maintain redundant data which means they offer no data protection for you.
RAID 1 arrays consist of two drives. In this configuration one disk drive is a mirror of the other, meaning they both have the same data on them. The upside of this array is an increase in performance, boasting 2x the read rate of a single disks. However, this comes with the downside of limiting your capacity to 50% of the total disk space.
Raid 10 arrays consist of two or more equally sized RAID 1 arrays. The data in a RAID 10 array is both striped and mirrored. This gives you both an boost in performance as well as data protection. The main downside of a RAID 10 array is that any drive segment is limited to the smallest drive in the array.
RAID 5 arrays require a minimum of three disk drives. For redundancy this array uses data striping and parity which also provides data protection and a performance boost.
The upside of this is that parity data is error-correcting redundancy that is designed to re-create data if a drive fails.
The downside of RAID 5 is that the drive segment size is limited to the smallest disk drive.
RAID 50 arrays are built from at least six disk drives configured as two or more RAID 5 arrays. This configuration stripes stored data and parity across all disk drives on both RAID 5 arrays.
The upside of this configuration is parity data provides data protection while the striping provides a performance boost. RAID 50 also provides high data transfer speeds.
The downside is being limited to the smallest disk drive for segment size.
RAID 6 arrays are also referred to as dual drive failure protection. This array uses data striping and parity data for redundancy. What sets this array apart is that it includes two independent sets of separately striped parity data.
The upsides of this setup is that you are extra protected. A RAID 6 array can recover from two simultaneous disk failures. Your maximum stripe size is also dependent on the number of disk drives in the array.
The only downside of RAID 6 is that the extra parity slows down performance.
RAID 60 is similar to RAID 50. The main difference is that RAID 60 requires 8 drives and contains two RAID 6 arrays. This configuration provides enhanced data protection because it uses two sets of parity data and the striping provides a performance boost.
RAID 60 arrays provide high data transfer speeds as well.
So which RAID is best?
For a balance of redundancy, disk drive usage and performance RAID 5 or RAID 50 are great options. They provide redundancy, allow for the largest range of disk usage and give you data protection that you can rely on.