What are some alternatives?
When comparing Amahi Home Server and Rockstor, you can also consider the following products
FreeNAS - FreeNAS is a storage operating system strong and robust enough to meet the needs of enterprise level businesses.
OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
Zentyal - Linux directory, domain, mail, gateway and infrastructure server for SMBs.
NAS4Free - NAS4Free is the easiest and quickest way to install an Open Source free NAS server. From home NAS to enterprise network storage, NAS4Free is trusted by thousands of installations every day.
ClearOS - A very good alternative for Windows Server, for free
unRAID Server - A scalable, consumer-oriented, server operating system.