A network-attached storage (NAS) device can back up all of your computers while always on in the background, saving you the need to find and plug in a portable SSD or external hard drive. It’s also a computer that can sit on your network, letting you offload tasks that would otherwise run unattended on your laptop, Mac, or desktop PC.After testing six new NAS devices and comparing them against our previous picks, we found that the Synology DiskStation DS225+ is the best home NAS for most people. It’s one of the fastest media servers we’ve tested, has a forward-looking 2.5-gigabit Ethernet port found on new routers for speedy transfers, and comes with software that’s easy to use.