I have recently installed a IBM x45 with two DS4100 (SAN) and due to space constraints it is generating too much noise in adjacent rooms.
Are there any good ways to isolate the noise from servers? There doesn't seem to be much vibration, but the majority of the sounds seems to be from the fans and disks.
Does anyone have experience with putting sound absorbing materials in server rooms/closets? I'm thinking about covering the surroundings in rubber or something.
Try this...
XRackPro2 Noise Reducing Server Racks
http://www.xrackpro.com/
They're common-place in the audio recording industry and would fit this purpose...
There is a reason OSHA frowns on housing server-geeks in the same room as their servers, and you just found it.
I have heard of accounts of people doing this, but the problem quickly moves from sound to airflow/heat. Once you construct your sound-resistant box, the next step is ensuring there is enough airflow into and out of the box to keep the gear comfortable and that creates openings for sound to get out. Which in turn causes some large ducts to be created to keep the noise down (insulate the ducts so sound is dampened along the length) while allowing air exchange.
http://www.acoustiproducts.com/en/ucoustic_wood.asp
The XRackPro2 cabinets are good but they are certainly not the best. The best are sold by Acoustiproducts. The reason I'm able to compare is that Acoustiproducts have a studio where you can go and compare the noise leakage of the different cabinets. They sell the XRackPro2 too, so they are not unfavourable about it, but if you can afford it, they recommend the 'Ucoustic' range. I went along and compared these, and the difference is really marked. So much about noise pollution isn't about the level of db, but it's about tonality and perception. I can't imagine putting either in a recording studio though, it must be a budget recording studio that has server cabs in the monitoring room and not in some purpose built annex somewhere else in the building!
I have had two of the Ucoustic models, one is a passive cabinet, and my lastest is an active cabinet. The great thing about the active cabinet is that you can attach two ducts to it and route this out of your windows (I had my window replaced with glass that had two holes cut out of it so they could be routed straight out, much like air conditioning vents). Of course, if I want free heat, I can simply remove the pipe and let the air circulate in the room, but in summer I'd much rather expel it. Servers do blast out a lot of heat.
The second, third and fourth benefits of the Ucoustic rack are: they are very heavily built and act like a safe to deter theives, they are graded as fireproof or at least meeting industry fire protection standards, and they can be fitted with a dust filter to aid longevity of equipment.
In addition to sysadmin1138 's answer, (You could technically do this in-place of, but I think they work best in conjunction) is to put in place baffles around the exhaust of the servers, and place the enclosure on top of a vibration-resistant pad of platform. The pad on the bottom (such as yoga or weight-bench foam pads) reduce the amount of vibration. The baffles serve to reduce the amount of noise that spreads ambiently after it leaves the server enclosure. It's important to note that you're going to have to balance the restriction of airflow versus the amount of noise.
I think it could be done with about $20 of lumber (2x2' pine boards should suffice) and some old t-shirts. I'm probably going to need to do it later this year.
I very much agree with sysadmin1138 - as long as you're not living in Greenland, Alaska etc., you might run into the issue of 'too much heat'.. You really need to think about an AC/cooling solution.
Nevertheless, you could cover your 'server room' with Noise Reduction Foam, like many audio studios do.
But those insulators are really expensive. If you don't dare about the look (and some chemical smell in the beginning), you can easily build yourself a template out of card board and use elastic foam spray from the hardware store to recreate such foam panels in a cheap way. They won't work as well as the professional panels, but they'll knock off quite a bunch of noise.
I did this for a small, hand crafted server 'cabinet' in my old attic. If you're patient (and crazy) enough like I was back then, you'll prepare a template with hundreds of nails put through the bottom of the //// template (it'll look like a part of an iron lady) - the nails will leave holes in the foam panel which will catch some more noise.
In my experience, as long as the server room has the recommended level of fire-protection - it will be virtually soundproof by design ^^