All good, I'm just sitting here working (3am), waiting for some of the India crew to do some stuff so killing time.

They're standard 1U (1.75" height) rack/rail mount servers; in this particular case we run on Oracle (Sun Microsystems) X4100 and X4100 M2 systems.

[www.rhfive.com]
^ looks like one of those.

[www.rhfive.com]
^ rear/open view

They're dual CPU (2 physical CPUs) AMD Opteron's of varying types; and between 8 and 32GB RAM (which 13 years ago was fairly decent; now not so much) and 4 x SAS (serial attached scsi) 15,000 RPM hard drives (280GB each I think) in RAID5 array (1 disk fault tolerance). On the open pic above you can see 2 x copper heatsinks, one on each CPU; in front of them there's an array of high RPM fans that push air straight through the system, front to rear.

[www.hpe.com]
^ most data centres, colocation companies etc look something a bit like this. I've never seen ours; it could be running outside next to a crack den for all I know. Each floor tile is 60x60CM so full size rack is typically 120x60CM (47.2 x 23.6 inch).

If you don't know much about data centres, a standard rack is 42U high; so in theory, you can fit 42 of those servers in 1 rack (in practice you'd probably have network gear/patch panels/etc in there too so actual capacity a bit less, and limited by power draw). Lots of blinking lights. Most servers aren't 1U though; it depends on their performance, capacity etc (1U tends to be a bit more expensive than an equivalent spec 2U system because more has to be crammed into smaller space; colocation companies etc charge typically on a per-RU basis so a 2U system might be a bit cheaper to buy than a 1U one; but costs for us 60% more to host).

Beyond being built to go hard 24/7, enterprise servers (like these ones; not proper midrange/mainframe systems) are really just loud PCs. They tend to have the most reliable components you can get, and don't usually come with an operating system installed, so you install your own. Most companies will have some variety of standard build for their operation. We just use off the shelf Ubuntu Linux (customized).

The systems I have my eye on trying to acquire are HP DL360 Gen10s; dual 10 core xeon CPU, 128-512GB RAM and 10 x 3TB disks (possibly flash; need to confirm). If I can swing that then I'll be happy and DK can do some work.
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