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Open rack vs. enclosed cabinet

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by silentsound

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I'm looking to move my servers to a rack/cabinet in a 7-ft by 5.5-ft room. About 6 tower servers, 1 rack server, 4 rack switches, 3 rack routers/telecom, and 3 non-rack UPS.

Would an enclosed cabinet work in terms of cooling? Any general recommendations of open rack vs. enclosed cabinet? Not much literature on the topic...

15 replies

by charliespencer

An enclosed cabinet has to vent the heat somewhere, and it's going to be into that small room. After a few minutes, the room will be quite warm, and the cabinet will be recycling the same heated air.

by silentsound

Thanks for your reply.

Wouldn't an open rack equally have to vent the heat generated from the equipment? I'm not seeing how the heat generated between an open rack solution and an enclosed cabinet is different.

The room will have a HVAC vent, but it does not have a raised floor or sufficient ceiling space to install a dedicated HVAC system. The enclosed rack I was looking at had a fan at the top, perforated rear door, and perforated sides around the plexiglass on the front door. It was on casters and it would be the only rack (and thing) in the entire room.

My goals for the rack/cabinet are mainly:
- to protect the equipment from general dust
- provide a stable physical environment (safe from bumps, hits, etc...)
- have a setup that allows easy maintenance and setup, but nothing regular
- protect against accidental pulling of cables (the room is also the telco
closet open to telco companies)

by jdclyde

while in the enclosed case you have vents, the open rack is completely open.

Think of this as the difference between cracking a window vs taking the rag top down. Much more air flow.

Also, the enclosed cabinet will run over twice the cost and I don't think a single cabinet would hold all of your servers.

by charliespencer

Yes, an open rack will also vent the same amount of heat into the room. I just addressed the downside of the cabinet without providing any alternatives; I apologize.

Your intitial post didn't mention you already had AC in the room. Is the existing vent tied into the HVAC for the rest of the building? This could be a problem when winter gets here and someone turns on the heat for the surronding rooms! If you know only cold air is going to come out, talk to whoever does your mainenance and see if they can put a return in the ceiling.

I've got one small comm room against an outside wall that I cool with a window unit, but it doesn't have the amount of equipment you have.

I don't know about anybody else here, but I've found a simple rubber door strip to be a satisfactory solution to dust. Our company policy doesn't allow telco employees (or any other non-company employee) on the premises unaccompanied.

by jdclyde

The enclosed cabinets are more for security than anything else to keep people from getting physical access to the equipment, as most security can be bypassed at bootup with in a few minutes.

Too bad you have 6 towers instead of all rack mount. I LOVE my IBM rackmounts. Just a bunch of drawers that you pull out as you need. Much nicer to work on and in.

Just get a rack, leave a space between the equipment ESPECIALLY switches and routers! People will put them right on top of each other without a gap for air flow.

Just put a lock on the door and make sure that the room has air flow to pull the hot air out if air conditioning is not available.

I even like to have a fan behind the rack to help pull the heat off of the equipment.

If your not looking for the physical security, the enclosed cabinets are just going to make it harder to get at anything that you may need to work on.

Mind you, there might be high end cabinets that have cooling but that is going to be some major bucks.

by silentsound

In this environment, security is not much of a concern. I have to admit I'm partially sold on the appearance of an enclosed rack... IT with aesthetics :P.

Unfortunately, only 1 rack server. We had no rack until now, so tower PCs were the preferred choice.

I agree with you about spacing. I've always left spaces between each component.

The room has air conditioning, but no other air flow mechanism. Anyone can recommend an inexpensive air flow device for a room this size (7ft by 5.5ft) with no access to windows? It would have to be very quiet as there are offices very close by.

The cabinet I'm looking to buy is used, so the cost is significantly less. The APC racks have some impressive cooling mechanisms, but they're up in the $1,500 minimum.

by dmambo

Despite being able to pull the gear out, I'm often frustrated that I have very limited access to the back. My rack is not on casters and the furniture is tight to the side. I'd leave access open to the back of the rack if possible.

If security's an issue for you, There are closed racks that are made with screen types of doors/sides. This eliminates the venting issue. I know HP makes some. Price is steep.

by jdclyde

not a rack problem.

When I took over as the Admin for sys and net, one of the first things I did was to MOVE our three racks, as the imcompetent people that put them in had them pushed too close to the back wall. I at that time had ADVISED moving them out further, but what did I know?

within a week of them being put in, the existing admin found she could not get behind them to work on anything (what a suprise) so you had to lean from the side.

Proper placement, your biggest person should be able to walk completely around the rack to be able to get at anything, at anytime.

by silentsound

The environment here used to be much the same. This will be the only thing in this room/closet, other than the telco punch down blocks and DMARC (but all this is wall-mounted and takes up very little to no space).

I'll probably center the rack as much as I can in the room, while still allowing access to the punch down blocks for the telco guys. I figure that, since it's on casters, I can move it around when I need more room (given proper cable slack).

by jdclyde

not a rack problem.

When I took over as the Admin for sys and net, one of the first things I did was to MOVE our three racks, as the imcompetent people that put them in had them pushed too close to the back wall. I at that time had ADVISED moving them out further, but what did I know?

within a week of them being put in, the existing admin found she could not get behind them to work on anything (what a suprise) so you had to lean from the side.

Proper placement, your biggest person should be able to walk completely around the rack to be able to get at anything, at anytime.

by ni70

I'd go with the 4 post steel open floor mount racks, as on aluminum racks the threads tend to strip quite easily. You'll want to put the racks in the center of the room, so that you'll have room in the back to work (as mentioned in previous comments). I don't know your floor plan layout. If possible get a ceiling mount air conditioning unit for the room. Guaranteed your network equipment will generate enough heat to heat your room (closet, as 7x5.5 seems quite small). You'll also want dedicated power circuits specifically to your room. You'll probably want one wall to be plywood for your DEMARC (if this isn't located in another room), your patch panels (unless their rack mounted)and your PBX phone switch, along with associated punch down blocks. You'll also want your ventilation to be filtered.

EDIT: If still in planning stage, I'd also recommend no heat source in the room, as stated above, your equipment will generate enough heat.

How old are your tower servers and who manufactured them? I know newer Dell PowerEdge towers you can get rack kits for.

I researched planning for a new network/telecommunications room a few years ago and really couldn't find any floor plans, but found a lot of usefull information and advise here on TechRepublic. If you'd like to see my CAD drawings send me a private message.

by jaqui

the reaction we got from a cable tech one time.
we had just finished putting a new structure together for local pub.
fully installed the electronic entertainment system.
all controlled from one rack / panel behind smoked glass door behind the bar.

the cable service tech was calling the office to say he had a 4 hour job to hook cable service into the system.
he left 15 minutes later with job completed.

our rack was hinged on one side, the whole unit swung out exposing the wiring on the back between units for easy access.
designed like that cause we were making our living installing the electronic systems in local pubs.

it was The Active Pass pub.
( Just for Oz, since he can check it out next time he's in the area )
108th ave and 148th street Surrey

by silentsound

Unfortunately, I don't have the luxury of planning and designing this room (closet, like you said) from scratch. It was already the telco room with DEMARC, punch down blocks, and PBX phone switch (which is a tower PC server, actually). The rest of the space was used by shelves for storage (these have been moved out). This is more of a relocation of existing equipment than the planning of a complete data center.

From the other posts, it seems the concern is not the rack vs. cabinet (other than ease of access), but the cooling in the actual room. There is a dedicated AC vent in that room, although I doubt it can be separated from heat in the winter. I'll check with the building management.

The room is surrounded on all sides by other rooms in use, other than a storage room. The door has a small gap under it, so air can escape there. I can look into adding a fan in the ceiling, but I'm not sure where the air will escape to. A real concern, since this is a small business, is cost. The enclosed rack I'm looking at is a used model, definitely not a new $1,500 item (or $500 for a 4-post rack).

The PowerEdge servers were bought in 2001. I've seen the tower-to-rack conversion kits. www.racksolutions.com has sliding shelves that would probably work just as well.

by silentsound

I understand the difference between the open rack and enclosed cabinet models.

My question was that, from Palmetto's comments, it sounded like the heat in the entire room was the problem. I didn't understand how a 4-post open rack or an enclosed cabinet made a difference there. The heat is still in the room at the end.

From the other posts, I'm getting the impression the issue is not really the open rack vs. enclosed cabinet question (other than ease of access and personal preferences), but it's more a question of air flow in/out of the room.

by silentsound

So, if I understand your post, the rack vs. enclosed cabinet is not really the question. It's air flow in the room that needs to be considered.

The vent is tied to the rest of the HVAC in the building. It's hard to get any modifications since this is an existing room. I'm not sure what you mean by putting a return in the ceiling... Do you mean a vent to pull in air instead of just one to push it out?

Unfortunately, the room is not near any windows, not that this would help since the windows can't be opened (5th floor / building aesthetics :P).

I hesitate putting a rubber door strip, since I figured the gap under the door aided in air floor. It would be hard for someone to stay with the telco guys when they're working, due to the size of the room. But this is really a minor concern... I just threw it in for completeness.

Right now, I'm thinking of buying the enclosed cabinet with the HVAC vent in the room. If an open rack becomes absolutely necessary, I figure I can just remove the sides and front/rear door. Since this is a used model, the cost for the cabinet is less than a new 4-post open rack.

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