What are some alternatives?
When comparing Drive Bender and Zentyal, you can also consider the following products
StableBit DrivePool - State of the art, file based drive pooling software.
ClearOS - A very good alternative for Windows Server, for free
OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
mhddfs - The driver combines a several mount points into the single one.
NethServer - NethServer is an operating system for Linux enthusiasts, designed for small offices and medium...
unRAID Server - A scalable, consumer-oriented, server operating system.