A NAS is simply an appliance (read: box with one or more hard drives) that provide storage for files and serves them over the network in your home. It is connected via Ethernet to your router. Since it is on your network, ANY device that connects to that network can read files or be served files from the NAS. So a single NAS can serve files to PC’s, Mac’s, Sonos, Apple TV and any other device – and it can do it all at the same time! NAS’s are small, can go anywhere and are meant to be on 24X7.
A NAS comes in one drive, two drive and four drive configurations. Obviously, the more drives, the more expensive. When the NAS ships with 2 or 4 drives, it is usually able to be configured in what is called ‘RAID’ mode. There are several flavors of RAID but essentially it copies all the music to the other drives for redundancy and theoretical ‘backup’. So if one of the drives fails, the other will start operating in its place.
RAID DOES NOT MEAN BACKUP! If the NAS gets crushed, dropped, damaged or a power supply fails, then your files and your music is gone. I’ve learned from experience to backup a NAS. I had 2 drives out of 4 total fail. Theoretically, you were supposed to be able to restore all the files by replacing the two failed drives with new ones. However, it did not work and I had to restore all my music from an outside backup (USB drive). All the NAS’s now ship with either Time Capsule/Time Machine backup compatibility (so if you are a Mac household you can add the NAS). If you don’t have Time Machine, then you can hook up a USB drive to the NAS and have its own backup software work to keep everything backed up from the NAS on a daily basis.
Modes of RAID: There is RAID1 which ‘mirrors’ the data from one drive to the next. Thus a two drive, 2TB system ships with (2) 1TB drives and you have only 1TB of available storage, the other drive is a mirror copy. There is RAID5 and other X-Raid technologies that work with 4 drive systems. It spreads the data across 4 drives and when one fails, the RAID technology will rebuild the RAID array. Suffice it can get complicated so best to talk or research to the manufacturers directly about their RAID choices.