recommended hardware settings for data and management nodes (no replies)

Hi, what would be a recommended hardware settings for data and management nodes? I know all of you would think to answer that it depends on my needs but I would like to gather information in general terms, I am going to setup a four node cluster (2 data + 2 management/sql/nosql), the goal is to have a FreeRADIUS/MySQL cluster, and configure the FreeRADIUS to run on top of the sql nodes, I believe Sun Solaris will be my platform of choice but there are *MANY* server options with *MANY* possible configurations, so in general speech what server requirements for these four servers will be capable of tun a very decent FreeRADIUS/MySQL four node cluster?

Thanks in advance!

ALDo