NAS can support various RAID levels for redundancy depending on the model. RAID is used by NAS devices to protect data in the event of a hard drive failure. NAS devices usually have four common RAID configurations. They are RAID 0, 1, 5, and 6.
The most commonly used RAID configuration is RAID 1. In a RAID 1 configuration, the drive where you store your data is cloned in a RAID drive. If you lose data on your primary drive, you will be able to recover it from the RAID drive.