What are RAID levels?
RAID levels provide increasing types of data protection the higher the RAID level chosen, albeit sometimes at performance and cost.
Historically RAID 5 with a single hot spare was fine when disk capacities were around 200GB and a RAID rebuild would take 8 hours. Today with 12TB+ drives a rebuild could take weeks and it whilst this is happening your system is most vulnerable.
The most common RAID level we provide today is RAID 6 as this provides good performance whilst at the same time providing double parity protection against data loss in the form of two drives.
RAID stands for Redundant Array of Independent Disks. RAID is a method of combining several hard drives into one logical array of disks to provide fault tolerance and protection against data loss. As drive sizes increase both for hard disks and SSD’s the risk of losing data increases the longer the system is rebuilding a failed or faulty drive.
Choosing a suitable RAID level depends on the software application and its performance requirement, normally measured in IOPS (Input Output Operations Per Second). Whilst a RAID provides access to data in varying levels of protection, do not solely rely on this to store data. Always back it up or replicate it to another system as there are occasions when a RAID system will fail due to controller failure, power surge, malicious damage, human error etc.
It offers fault tolerance and higher throughput levels than a single hard drive or group of independent hard drives. RAID levels 0, 0+1, 1, 10, 5 and 6 are the most popular types of RAID, however, RAID levels 50 and 60 also exist.