The DiskStation DS213Air is the fourth dual-bay NAS server I've reviewed from Synology and it most resembles the first one, the DS209+, which came out more than three years ago, at least in terms of drive-bay design, in that you have to open its chassis to install or replace the two internal hard drives.
Other than that, this new server shares all the features you've seen in other Synology dual-bay servers since it uses the latest version of the DiskStation Manager (DSM) operating system, version 4.1, which most other existing servers can upgrade to.
The DS213Air does have a feature of its own, however: it's the first from Synology that comes with built-in support for Wireless-N Wi-Fi. In addition to being a NAS server, it can also work as a Wi-Fi access point or even a wireless router.
The server did comparatively well in my testing, though it was slower than most of its cousins. But it's also the most affordable one -- $330 with no storage included. If you're looking for a budget-priced yet full-featured NAS server for your home, the DiskStation DS213Air makes an excellent investment. If you want something that offers better performance, more storage space, or both, I'd also recommend Synology's DS712+, DS412+, or DS1511+, or the QNAP TS-469.
Design and setup
As I mentioned above, the DiskStation DS213Air's design is, in a way, a step backward, compared with recent servers from Synology: it doesn't offer an easy way to install and replace its hard drives. Instead, as with the DS209+, you will need to open its casing for this job. While this process isn't as hard as it sounds -- half of the server's cover slides off very easily once the two screws in the back have been undone -- it's rather inconvenient and means that you can't hot-swap drives. For most home environments, however, where it's generally OK to power off the server for a while, this is not really a big deal.
On the back, the DS213Air has just two USB ports and one Gigabit Ethernet port. This is rather limited; the DS712+, for example, also comes with an eSATA port and has two Gigabit Ethernet ports. To make up for this, the DS213Air's USB ports are both USB 3.0-compatible, offering much faster speed than those of the DS712+. You can use these two ports to host printers or other storage devices. When a USB printer is connected, the DS213Air will also make it compatible with both Apple AirPrint and Google Cloud Print, even when the printer by itself is not compatible with these services.
On the front, the DS213Air has nothing but the power button and an array of LEDs that show the status of the server's power, the wireless network, and the two internal hard drives.
As with other dual-bay servers from Synology, the DS213Air's two internal hard drives can be configured using all the possible RAID setups available for a set of two hard drives. On top of that it supports Synology Hybrid RAID, which makes it possible to dynamically scale up the number of drives in the RAID, increasing the RAID's storage capacity without having to rebuild the RAID from scratch. With Hybrid RAID you can also use hard drives of different capacities, as along as you only replace the existing hard drives with drives of the same or larger capacity, and make sure there's at least one hard drive being used as redundancy for data safety. In the particular case of the DS213Air, since the server supports a maximum of two hard drives, Hybrid RAID is very similar to a RAID 1 configuration.
As with other NAS servers from Synology, savvy users should have no trouble getting the DS213Air up and running. Even the part that takes the longest, which is the RAID building, was very fast in my testing -- just a few minutes with two 1TB hard drives.
Home users may find the server harder to set up, however. The NAS server comes with a desktop application called Synology Assistant to help with initial setup and installation of the operating system if you buy a diskless unit and install the hard drives yourself. In this case the Synology Assistant will download and install the server's firmware directly from Synology's Web site, saving you from having to manually download it on a computer first. While this step makes life a little easier, the Synology Assistant generally doesn't provide enough information on what it does, giving the wrong impression that the server is hard to use and doesn't have much to offer. To find out how untrue this is, you'll need to use Synology Assistant to launch the server's Web interface (by the way, the default log-in credentials are admin for the username and the password is blank). Now an entirely new world opens up.
Like Synology's other NAS servers, the DiskStation DS213Air uses the DiskStation Manager (DSM) operating system, which is currently at version 4.1, and therefore shares all the features this OS has to offer for a dual-bay server.
This means its features are very similar to those of the DS412+, the DS712+, and the DS1511+. But as I mentioned previously, the DS213Air does have a feature of its own: it's the first from Synology I've seen that comes with built-in Wi-Fi functionality, and can work as either a Wi-Fi client, a Wi-Fi access point, or even a Wi-Fi router. The DS213Air supports a single band (2.4GHz) of the Wireless-N standard (802.11n).
Since the server has only one network port, when working as a Wi-Fi router it can only host a network made up of wireless clients; in other words, you won't be able to connect a wired client, such as a desktop computer, to the network. The server worked well as a Wi-Fi client, in my testing, allowing itself to connect to an existing Wi-Fi network. In my opinion, it's not a good idea to use the router this way, however, because the data performance of the router is limited to that of its Wi-Fi, which is Wireless-N. Wireless-N is generally not fast enough if you want to serve data to multiple connected devices, which is the main purpose of a server.
The best way to use the router's Wi-Fi is as an access point. In my testing, though this function worked well, Wi-Fi clients connected to the server's wireless network were separated from the local network to which the server was connected. The server creates a network of its own, on top of the existing network.
All in all, the DiskStation DS213Air's Wi-Fi support needs some work and would be better if it supported dual-band and even the upcoming 802.11ac standard. For now, however, it will serve well enough if you just want to bring Wi-Fi to a far corner of the house where you want to stash the server.
Now let's move on to the server's other features, which it shares with the rest of Synology's NAS servers and are controlled via its Web interface.
The server's Web interface -- which resides within the window of a browser, such as Internet Explorer or Firefox, that you use to open it -- is very similar to the GUI of a native operating system like Windows. You can open multiple windows and resize them, move them around, and so on, all from within the Web page. There's also a control panel where you can customize server settings; each has its own icon. There's a taskbar that displays a button for each window being opened, a package center where you can add and remove packages (aka applications), and a Start button that pulls up icons linked to installed applications. All in all, everything is very well-organized and intuitive and is a delight for savvy users.
From within the Web page of the server's Web interface, you can manage multiple things at a time, such as adding new users or new share folders, or searching for a particular file, and so on, in separate windows. There are even fading effects as you move from one item to another, and you can change the background photo. In fact, when opening the server's Web interface in a browser's full-screen mode, you can easily mistake the server's Web interface for the GUI of a Linux desktop, as though you were working with a computer directly. And while all that's already really cool, it's still the least interesting part of what the server has to offer.
The server comes with built-in features (aka settings, accessible via the Control Panel) and features that can be added via packages. It would take too long to list all these settings, but the server basically supports everything you can imagine for both home and business environments, including really advanced functions such as iSCSI, support for Active Directory, a VPN server, and virtualization. I actually tried most of these settings out, and they were all well-designed and easy to use. For example, when you choose to add a new user, you'll be prompted to set that user's access to the existing share folders (full access, read-only, or no access), and assign which applications that user will have control over. And when you create a new shared folder, you'll be prompted to determine existing users' access to it. All of that can easily be done with a few clicks. All of the router's settings offer a great level of depth and integration. Consider what I mention in this review to be the tip of the iceberg.