Most of computer users are used to back up files and folders to an external hard drive, but when the network has multiple devices and more computers, backing up to an external hard drive does not mean always the right choice.
Network Attached Storage, better known as NAS is a very reliable backup solution that is plugged in directly into the network and is shared by multiple devices. What the user only need to do is to synchronize each backup and the software will take care of sending the files to the NAS.
One of the major difference between the NAS and a traditional backup is the redundancy of the NAS that is accomplished via RAID. Whereas a traditional external hard drive may fail because it has only one hard drive, a NAS may have two or more hard drives that are synchronized in RAID, meaning that if one hard drive fails, the other will collect all the data from the faulty drive and keep functioning.
Buying a NAS with only one hard drive does not make any sense, first of all because it is more expensive than an external hard drive and also because it does not provide the redundancy that makes the NAS a very reliable backup service.
A small business with 5 to 10 computers should have a NAS in RAID 1 with two hard drive of at least 2 TB each. Large corporations should attach NAS where every server resides. Nas service offers also encryption technology which allows to secure your files in case somebody has unauthorized access to your computer.