Planning a Small Server Room

An anonymous reader writes: "Our company is planning to build a small server room. Initial requirements are for two or three enclosed server cabinets in which various servers and network gear will be installed. The cabinets are planned to hold between 15 to 20 servers of various types and sizes, switches, routers, four dial-in modems for after hours use by staff who do not have ISPs and a KVM switch. We would expect for a small desk as a work area, a book case, storage for some spare parts as well as server documentation and records. We know that we need some power protection in the way of a UPS and a generator. We also expect that this room will get quite warm in the summer months so it will need more air conditioning than the rest of the office. What should we expect for power and cooling needs? Are there any 'rules of thumb' when it comes to building a server room. Good suggestions and help would be appreciated."

Comments

Accessibility

[Webmoth]

Lots of good suggestions here, but I don't see any mention of accessibility (yet).

Make sure that you can walk -- and stand up -- BEHIND your servers. Make sure you can open cabinet doors fully. Make sure you can pull a server out of the rack without moving stuff around. Be able to have two people in the room: one in front and one behind the rack at the same time. Make sure you don't have to move the rack to work on it.

You want a server ROOM, not a server CLOSET. I've seen far too many situations where work on a server involved crawling under desks, moving stuff, craning necks. Hey, moving computer while they are running is A BAD THING: you don't want heads crashing into a hard disk platter. Besides, you risk knocking the (power) cords loose, something I've done on several occasions. I've got one customer whose server closet is so small I have to move the rack forward to access the back and then push it back to access the front again.

I would say that you want at least 3 feet in front of and behind the rack. Typical racks are nearly 3 feet deep, so you want your server room to be at least 9 feet in one of the dimensions.
Now placing your rack in the middle of the room means you have to get your cabling and power to the middle of the room. Having your patch panel or power outlets on the wall just won't cut it. Use either overhead cable trays (NOT conduit) or a subfloor with removable tiles. Don't run cables above a drop ceiling from point to point in the server room (cables headed out of the room are OK to be in the ceiling). NEVER run cables across the floor.

Bolt your rack to the floor so you (or an earthquake) don't knock it over.

DO NOT allow non-network junk to clutter up the server room. That old dot matrix machine gun that nobody will ever use again but you can't bear to throw away can go in a storage closet somewhere else.

Again, give yourself elbow room. It may be hard to convince the person with the purse strings to pay for space ("but the server will fit in a 3' x 3' closet, why do you need a 10' x 12' room?") that will be mostly empty, but it will make your life easier and will -- practice saying this -- REDUCE UNPRODUCTIVE DOWNTIME. Make sure you get the "unproductive" in there.

A few suggestions

[acaird]

For the size room you're making, instead of a raised floor, consider a cable tray (basically, a ladder a meter from the ceiling) in which you can lay cables. Raised floors are better, but also cost a mint and aren't always practical to install.

• Also, as everyone said, power. keep in mind that the UPSes you'll need probably don't plug into normal outlets; pick them out, and call the electrician - Hubble twist-lock-y things are what you need, but check out APC (and other) web sites for the specs on the plug; you don't need to know what they mean, just copy them carefully for the electrician.
• The portable air conditioners are nice, but still need drains - talk to the facilities people while you're doing the lay-out - if there are pipes in the walls in a convenient place, take advantage of them and put the A/C units by them.
• Don't worry too much about humidity. back in the day you had to 'cause there was paper in the computer rooms from the big line printers. i doubt you have that, so make sure the A/C people realize that and don't sell you super-fancy humidity controls that you likely don't need.
• As has been mentioned - a meter behind the racks, and 2 meters in front, computers are heavy and the more space you have the easier it will be to get them in the racks.
• IMO, don't use it for storage, no shelves, no drawers in the desk/table, etc. It's a machine room, not a storage room. Put the computers in, and stay the hell out. It's temping, since it's locked, and probably not full, etc. But don't do it, you'll lose control really fast, and it'll be a disaster.
• Again, power: circuits, and more circuits. However many you have, you don't have enough. One room I designed has two 30A circuits per rack, and in some cases that's not enough, mounted on the cable tray so cords don't go back to the wall behind the racks - remember, you need to be able to walk (and carry heavy things) back there.
• Also, in addition to a phone, put normal old network jacks in the walls. I know, you'll have switches in there somewhere, but probably not near where you want the desk, and nor does the cable tray go there. If you're having cabling done anyhow, a few jacks right near the patch panel are cheap and well worth it.
• Leave room for expansion, pack it as tight as you can. Remember, when you add hardware, you need to add A/C and maybe UPS and power. Leave lots of room. If you're over 60-70% full today, you're in trouble real soon now.

Good luck.

Racks

[ag3n7]

Use third party racks that allow for variable sizing of rails and better cable management than the standard 'vendor' racks:

http://www.chatsworth.com/