We installed a HP rackmount server for a client around 2.5 years ago. The server, running RedHat Enterprise Linux, acts as a "controller" for multiple networks,both real and virtual and supplies internet, proxy server, VLAN,DHCP and security services to multiple companies all based on the same site.
The linux based server has only had 2 reboots since going live, once after the initial setup and one when the server was moved to a new location, which we feel is a pretty good track record !
It was a little surprising to find that the server had randomly shut down twice in the last week, killing the site services to all users. No errors reported in the logs, no errors reported in the BIOS, no errors reported via diagnostics.....it was obvious something was going to fail but which part ?