Hmmmm...
"If your core servers – and hence your core applications – live in a data centre, then by definition they're not on your premises."
And if we own the data centre?
If your core servers – and hence your core applications – live in a data centre, then by definition they're not on your premises. In many cases they may be hundreds of miles away – in fact, in a previous life, my employer's most distant data centre was six time zones away in the US Midwest. This means that you don't have the …
My core servers, and core applications are all in a data centre - or actually, multiple data centres - but as nearly all of them are virtual machines, and the hardware is NMP (Not my Problem) I no longer have to worry about IPKVM and Serial consoles.
I'm bloody glad they existed before the wonders of P to V made my life easier, though, "Smart Hands" support is no substitute for watching the thing boot yourself.
Console servers had been stagnant for about a decade or so, until Lantronix released the new SLC-8000 series. I've deployed two of them so far, and for those of you who are sick of console servers with grotesquely underpowered CPUs, 8-year-old vulnerabilities that are still unpatched, etc., it's a wonder to behold. It's fast & slick to use. The pin layout lets you connect Cisco console ports with a standard straight-through CAT-5 or CAT-6 cable (no adapters!). They're even adding USB console support for those things that have (gasp) moved beyond RS-232.
http://www.lantronix.com/it-management/console-servers/slc8000.html
I'm not sure I agree that an IP KVM is really a necessary thing. Both HP iLO and IBM's IMM have lights-out KVM access and you can get into the BIOS screen on both. In the case of HP iLO, even without the product being licensed; you only lose your console connection once the installed OS is up. IBM aren't so generous but you can still power cycle a machine with no license.
If you've got any reasonably competent IPMI baseboard management controller then you'll be able to remotely power down/up and likely a decent Serial Over LAN interface to access the BIOS should you need to.
The Dell iDRAC6 onwards is real nice for the built in KVM and remote media though ...