I am going to build a server for backups. I want to install the operating system on USB flash disk (a little space), and attach some hard disks for data (much more space needed). Because it is going to be backup, disks will run only once a day. So to save power I want disks to stop (spin off) while not used.
Do I need to buy some special disks for it, or is it enough to configure something in Ubuntu? I want to buy 2.5" disks, also because it is consuming less power.