CentOS 7 is a clone of Red Hat EL7. Without commercial components of Red Hat.
Good and cheap choice for general purpose SOHO server.
There are two ways of installation as master OS, not in VM.
a) use AHCI and software RAID of Linux (md) and listen noise of cooler forever.
use b120i para-RAID. Temperature sensors workig well, less CPU utilization during i/o (not confirmed, opinion).
a) - mount ISO throw ILO Remote console (if ILO not full - obtain 60-days license from HP for free,