Server/Network tools?

Hi all! ive just bought 7 NEC 5800 L120RD Express’s and im looking at ways to sort of monitor them and generally looking at software i can put on these servers (or any others) that i can use to remotely monitor them. Such as theyre all RAID 5 and so would like some kind of notification that one of the hard drives has died over the network etc that kind of thing. Im not sure if there is some kind of universal software that can tell you this or do i have to get individual software for each piece of hardware id like to monitor. Im just looking for the best way to be informed if theres a problem with a server of any kind, and so turn to you guys the experts for help!

Thanks all!