Yes, it works. It’s not only possible, but also easy.

After reading many blogs that advertised the famous “flashing the H310 card to IT mode”, I was able to install and run unRAID on my R520 just by using the hard drives in a non-RAID configuration, an option available by pressing Ctrl-R at startup, entering in the RAID card configuration and pressing F2 . That’s it. No fancy surgery with the firmware.

There are two RAID cards available for the R320, R420, R520 or R720 servers: H310 and H710. The latter has the cache and battery and it doesn’t have the non-RAID option. So, use the cheaper H310 and you’re done. unRAID, FreeNAS, they both work with that option.

With the very low noise and power consumption (1 CPU, 4 x WD RE4 2 TB and an SSD draws between 42 and 70W), my R520 can stay on 24/7 without worries about the energy bill.