I just received two neat Sun V20z dual Opteron 1U systems on Saturday. I'm preparing them for submitting an netfilter/iptables based commercial firewall product to participate in a multi-vendor benchmark.
I really like the AMD64 aka x86_64 aka Opteron architecture. For one part, AMD seems to have done about everything right. 8 more registers [optionally even in 32bit mode], transparent execution of 32bit and 64bit instructions. Not to forget the neat Hyper-transport interfaces, the built-in memory-controller, ...
But I've been working with an AMD64 system for almost a year by now.. so there's nothing that new about it. However, Sun takes this already brilliantly designed CPU and system architecture another step ahead.
If they would have contracted me as consultant to design a high-end server with all the features a power Linux sysadmin needs, I would have ended up with a very similar proposal.
Most importantly, nobody ever wants to have a monitor or keyboard attached to a Server. I wonder why vendors of server mainboards even bother to put a VGA chip or AGP slot on there. So the least you can expect from a decent machine is a real serial console - one that allows you to access CMOS Setup (erroneously referred to as BIOS) via the serial port.
The V20z is even better: Apart from your dual Opteron system, there is a whole separate independent second computer on the mainboard: The 'Service Processor'. This is actually an embedded MPC860 system with 64MB of RAM, running at 64MHz speed. And yes, it is running Linux 2.4.18 :). It has a separate 100-base-T Ethernet port, using which you can SSH into the SP.
Once logged into the SP, you can power cycle the Opteron System, monitor System Health, and access the Opteron Host system's serial console over LAN. This saves you from buying an extra serial terminal server, expensive serial boards and lots of extra serial wires. It even supports console logging on a NFS mount, including logfile rotation.
Everything is built using stock free software components. Linux, OpenSSH, conserver. You immediately feel at home. Oh, by the way: The SP is running ip_conntrack and ip_table by default :)
And yes, the box even includes a printed copy of the GPL (!) - however, no source code or any written offer included in the box :(