As someone who's managed a team of sysadmins that moved to the Linux world from Windows, I have this tip: "Reboot does not fix anything, it just hides things".
For some reason, Windows admins have been trained to reboot immediately when things don't work well rather than to figure out why something is failing. I'm sure this was a valid "fix" in older versions of Windows, but Windows has been stable for quite some time, and things shouldn't mysteriously stop working for no reason. Take a bit of time to figure out *why* the CPU is suddenly spiking on the database server, since if you reboot it, you will have lost most of the evidence for why it's happening, and it's likely to happen again. If it's a production server and you can't spend much time, run a few diagnostics (ps, "top", lsof, etc) and save to a file for the postmortem, but don't just go in and reboot before looking around.