Whether you are setting up a RAID to attach directly to a computer or connecting a NAS on a network, choosing a level of RAID depends on your requirements for performance and data safety. There are multiple levels of RAID, and each uses a specific method for data storage. Some of the most common RAID levels are:
RAID 0 (striping) divides data into separate blocks that are distributed over your storage devices. It provides the fastest retrieval to your files because drive access time is reduced. You need a minimum of two drives to use RAID 0.
RAID 1 (mirroring) creates an identical copy of all of your data onto another drive (or multiple drives). This helps protect the data should one of the drives fail, but you should always have a separate backup of your data in case both drives fail simultaneously—which does happen.
RAID 5 (striping with parity) requires a minimum of 3 drives and offers one of the safest RAID levels. With RAID 5, data is distributed along with parity data, which adds redundancy allowing the RAID to be rebuilt when one of the drives fails.