For evaluation purposes you can use Syneto OS for free. The unlicensed version is fully functional that can manage up to 1TB of raw disk space. You can install the software using either a DVD or USB image. For details, see the instructions below.

The latest stable version is 3.2.6. To learn more about the features read the release notes.

Install from DVD *recommended

Download the image and burn to a DVD.
Boot from DVD and follow the installation instructions.

Install from USB

Download the image and follow the USB installation instructions.