Server Room - DataCenter

Random thoughts on server room goodness.

• A low cost temperature sensor that can alert you of problems 
• Any lowcost webcam, plus Abelcam ($28)  and a TrackerPod ($125) can make an effective video surveillance system.
• The WeatherDuck ($199) + City Power Monitor ($40) (both available here) can track temeprature, airflow, light level, humidity, and presence of city power at an outlet. All this and it can alert you to problems when things go outside of defined limits.
• The WTI NBB series powerstrips ($750-$1000) will let you powerdown/powerup your servers remotely. Nice thing about these is they have two plug cords so you can easily put each server on two separate circuits. There are both web and telnet interfaces (sorry no SSH, but sniffing should not be a large issue as you will so infrequently use these).
• I have used the Baytech RPC series remote control powerstrips. These have only one power cord, but they measure current through the strip, which is nice because you can be sure you won't trip any breakers. Price is comparable to the WTI units.
• In the past I've used large high density switches and patch panels. So you'd have a patch panel in the rack, then another patch panel at your networking rack, and cabling would be server-->patch panel-->patch panel-->switch.  I think that these days, with multiple copper gigabit links, it may be cheaper and smarter (simplicity wise) to use a switch for each rack, then uplinked to a backbone switch. So, server-->rack switch-->backbone switch. BUT this is something you need to study carefully, keeping aggregate bandwidth requirements in mind.
• I believe that a server room should be a cold, dark, lonely place, only visited when you need to rack a new server or repair/upgrade the hardware. Thus I believe strongly in remote control, and remote KVM if you can afford it. Having spent a lot of time looking at remote KVM, I think Raritan Paragon is the best and most cost-effective system for larger server rooms. If you cannot afford that, you can look into 'normal' KVM plus something like this Aten KVM on the Net ($459)system which can convert your 'normal' KVM switches into a KVM-over-IP setup.
  • Note that if you can afford remote KVM or remote power strips, get the powerstrips. Most OS's these days have more than adequate administrative remote control setups, and the remote reboot capability can resolve many issues. Don't leave CD's in the drives ...
• Do you really need a monitor or $2000 monitor/keyboard drawer in the rack?
  • If you have KVM to all systems, consider just putting a small desk in a corner somewhere, and the keyboard/mouse/monitor there. Your feet will thank you.
  • If you don't have KVM, or would rather spend the money on something else, consider one of these rolling keyboard/monitor stands. Just plug in where you need to be! You might put a small UPS where the picture shows a computer; this gives it weight and the ability to run for awhile if your systems are running on UPS.
• Cable slack is a neatness killer. NeatPatch can help alleviate it. But you should be using proper-length cables whenever you have the option! You rarely have the option with power cords, SCSI cabling, fiber patches. Ugh.
• Don't go nuts on cable neatness, though. You'll see beautiful server rooms with ty-wrap every 3 inches; the truth of such beauty is that it will then take an hour or more to run a new cable or replace bad one. Obviously you don't want a big rats nest, but cable should be loose and relatively neat. It should have a few inches of 'play' at either end; never stretched tight. Remember that you're going to have to trace it, move it, replace it, work with it in various ways. Think longterm!
  • When recabling anything, strip all the cabling all the way out, then run it to its new destination. This way you don't have cables that spiral around one anohter and create problems later on. And yes, sometimes I have cheated by just cutting off one end and pulling from the other end. You can either toss the snipped cable, or put on a new end later.
• If you have a choice, go with cable troughs above the racks rather than raised floor. It is a lot easier in the long run; raised floor almost always ends up hiding an airflow-hogging, madness-inducing rats nest of Biblical Proportions. Your HVAC planners can still cool the room.
• Before you rack that server: use a Kill-A-Watt to measure its startup and steadystate current draws. Startup should be the heaviest power draw the system will have.
• Start racking your servers at the very bottom of the rack and rack upwards. Rack them tight; no spaces in between.
  • I see a lot of server rooms where spaces are left next to, say, the fileserver 'because we'll add another fileserver someday'. In reality this never seems to work out; you end up with either too much space left over, or not enough when you finally get that new system. Is it *really* that important to have all file/mail/database/whatever servers in the same rack? I say, not really. One possible exception: leaving space for future disk arrays.
• Place power management, switches, and/or patch panels at the top of the rack. (Actually I prefer vertical 'zero U' power bars.)
• I am a labelling freak. I believe good labelling prevents a lot of costly mistakes! I label servers front and back. I label power plug ends. I use a cheap P-Touch labeller to do it. Generally I don't physically label network ports with anything other than a number, though. Instead I use manageable switches and set the switchport labels there; then print out a list and place it on top of the switch.
• If a server comes with any sort of keylocks for the case, I am always careful to unlock all locks and throw away the keys so no one is tempted to lock them. This sort of thing is silly; only trusted people should be in the server room in the first place! A locked server + missing key is an embarrassing slowdown when problems occur or routine maintenance is underway. Even so, most of these locks can be defeated with a screwdriver if you're not afraid to break or bend the casing a bit. And why would a theif be ashamed of that?
• If the server comes with slide mounts and cable management arms, use them. It will make both emergency and routine hardware service that much easier.
• Rack doors: again, the security provided is probably less a concern than the hassle of keeping track of the keys. Airflow can be a concern especially if you are doing hotrow/coldrow or have strained your HVAC to the limit. For a simple check, keep a temperature log of the topmost server for a few days, doors on and again with doors off. If you can get away without the doors, you'll save some hassles. The temperature log can be from motherboard sensors or from this handy little USB unit ($60). Note that most server specs say ambient temps above 95F can lead to overheating. Check ambient temp wherever the server sucks air (most servers have a front to back airflow).
• Schedule HVAC maintenance no less than twice a year.
• Same goes for UPS maintenance and testing (okay, maybe once a year). How old are those batteries? Are the replacement dates for all batteries clearly marked on the front of the UPS?
• Generators, if you have them, need to be excercised/tested no less than once a month. You can probably test the transfer switch less often, though.
• Get a rolling tool cart. Besides providing a place to keep the tools, it's a handy place to set down your laptop if you brought it along. Also handy for moving servers around.
• Put a few of these cable hangers on the wall somewhere. Handy for keeping spare cables sorted.
• A few bookshelves are a good idea, for hardware documentation, software boxes, boot disks and so on. Periodically remove the docs/disks/boxes for the stuff you no longer use.
• On that bookshelf, in a red binder, should be a copy of your DR plans (you have DR plans, right?), along with any CD/DVD media you'll need to restore servers from scratch.
• If there's a phone in the room, equip it with a wireless, binaural headset (like this). When the chips are down, you'll be glad you did.
• Look around for emergency lighting. There isn't any? Get it installed, or at least get a rechargeable flashlight and keep it plugged in. Actually, get a rechargeable flashlight anyway; emergency lighting usually sucks. Also ask what happens to the cardkey locks when power is down.