We spend a lot of time in IT talking about the virtual -- packets, protocols, bits, and bytes -- while paying little attention to boring facilities issues like electricity and HVAC (heating, ventilating, and air conditioning). When we buy servers, we demand redundant power supplies but ask little about the power once we plug the server in. When we load a new server into a rack, we plug it into a power strip or daisy-chain power strips and plug even more stuff in. We assume it will all work out, and most of the time it does.
However, not understanding your electrical and HVAC infrastructure can have a profound effect on your operations. As servers and other equipment have gotten denser and more power-hungry, it's not safe to assume that electrical and HVAC issues will work themselves out. IT management should be actively involved in facilities issues.
I've been surprised by how much I needed to know about the electrical and HVAC systems in the facilities where I managed IT. In one building, we were on the same high-priority electrical-grid segment as the city fire department, so I rested easy. We never had problems. But sometimes the appearance of stability can be deceiving. During the height of the dot-com bubble, I was moving my company's Web infrastructure to a new datacenter within a major Tier 1 hosting provider. Before the move, I saw firsthand the massive backup generators and tanks of diesel fuel in the new facility, then listened to the spiel about they could run for days off the fuel on hand. This was a fine facility -- the Ethernet cable running in the bowels of the building was color-coded and visible through Plexiglas flooring in the hallways. Sounds perfect, right?
The new datacenter was awful; plagued by erratic power outages. And those bright and shiny emergency generators had a knack for failing when they were most needed. My initial visit occurred around the time that Intel-based server form factors were shrinking rapidly and many businesses were replacing slow 4U servers with dozens of fast and more power-consuming 1U and 2U servers, resulting in sharp increases in power usage. When the building was designed, a year or so before we moved in, the electrical plan assumed racks of mostly 4U servers, and I neglected to ask detailed questions about their capacity. The problem was fixed eventually, but a full investigation of electrical infrastructure moved higher up on my due diligence list after that.
The blazingly fast CPUs in those small boxes put out a lot of heat that can lead to some challenges. One problem I've seen illustrates the delicate balance between electrical and HVAC. Suppose you have a server room with limited UPS (uninterruptible power supply) capability because your company is a small business. Your limited budget encourages you to assume that any power outage will not last longer than an hour. Unless you have a massive UPS system, hooking your building's HVAC system into your UPS will drain the power almost immediately, but because most power outages are short, you decide to keep the servers running during an outage with no HVAC. If you play this game incorrectly, your servers will continue to run, but the room can get to the boiling point really fast. What is a cash-strapped IT manager to do? Simple: Keep a few cheap box fans on hand to blow the hot air out of your server room when you have to. And pray that the power comes back on soon.