Qnap's TS-439 Pro II is a strong business backup solution under $1100

The TS-439 Pro II uses the same D410 Atom processor as the TS-239 Pro II but supports up to four hard disks (either 2.5 or 3.5in) and an expanded range of RAID options.

These include those seen on the 239 Pro II. But more disks means that RAID 5, RAID 6 and various spare disk options are also available. This brings to bear much more robust crash protection than a two disk offering.

Setting up the device could not have been simpler. When three drives were plugged into the unit (all drives are hot-swappable) we were able to use the more advanced RAID options.

This is done using the supplied Qfinder application, which pushes the user to a browser based configuration application. The Qnap TS-439 Pro II also supports setup without a PC, using the front LCD screen of the device and a basic two button interface.

Qnap offers a vast array of configuration options with the TS-439 Pro II. While the built-in UPnP media server, iTunes server and bittorrent client are great for home users, this NAS is much more business focused, with the vast majority of features overkill for a home user.

Those in a SOHO or small business environment will find not only the expected file, print and web server options but also support for surveillance cameras, various backup systems including Apple's Time Machine, MySQL server and a host of other options.

Not only do the four drive bays provide a host of storage options, but the TS-439 Pro II also sports external expandability. There are a total of five USB 2.0 ports, with support for up to three USB printers. Alongside this sit two gigabit Ethernet ports configurable to support load balancing or various failovers. There are also two E-Sata ports that are designed for attaching backup drives.

We tested the NAS using Intel's NAS performance toolkit (NASPT) software over a gigabit Ethernet network. It recorded write speeds of 84.4MB/s in the copy to tests and 79.3 MB/s in the copy from tests.

The Qnap TS-439 Pro II really is a business powerhouse. It drips with features, is highly configurable and delivers robust performance. It is overkill for the home user, but for those wanting a business NAS this ticks all the boxes.