Protecting Hard Drives From Jackhammers

Faramir writes: "I need some help with a jackhammering problem. You see, construction is going on, oh, about 5-10 feet behind the wall of the lab I work in. Essentially right next to my head. And next to this wall I have a number of PCs and a file server with a bunch of nice SCSI drives. And I have no idea how long it is safe to leave them running." (Read more below.)

"I can look at the vibration tolerance specs for the hard drives (my main concern), but translating this into jack hammer vibrations is beyond my ken. Also beyond the manufacturer's tech support, as I suspected. Any clues? Suggestions? Thanks!"

Perhaps the same principles apply to protecting hard drives from loud music, but since heavy-duty laptops aren't much of a solution for holding a rack of SCSI drives, many of the options mentioned there might not apply.

Comments

Another problem to consider

[Anonymous Coward]

Is the PHAT Jackhammer of Vanilla Ice's beats when you've got a couple of gigs of MP3s of tha master's warez on your hard drive. That shit is so funky ain't no hard drive can stand up to it.

VI

El cheapo technique:

[Anonymous Coward]

Back when I was interested in holography, there was an "el cheapo" technique used to damp out vibrations. (Hey, if your building a basement holography lab, you can't afford the "good" [read: expensive] stuff.)

Anyway, one of the tricks, aside from the usual foam and stuff, was to get an innertube (from a bicycle or car), fill it only part way with air, and sandwich it between two sheets of plywood (or some similar material).

That will take out a lot of vibration.

Also, put a small mirror on your equipment. Bounce a laser (solid state laser pointers are a couple of bucks down at the drugstore/recordstore these days) off the mirror and across the room. It provides a good indicator of the vibration.

This guy is right, but if you can't move...

[unitron]

If you can't move, at least try to move the equipment to the wall farthest away and plan for falling ceiling tiles, plaster dust, etc.

Maybe you could temporarily arrange to work and have the equipment on during hours when construction isn't happening.

For a vibration and impact shock wave resistant material to go under the equipment, look for some stuff called Enkasonic. When I last looked into it, it was made by BASF in a facility of theirs somewhere in the western part of North Carolina. Look it up on Google. Good luck.

Re:This guy is right, but if you can't move...

[unitron]

It was the possibility of those jackhammers accidentally providing an unplanned entryway into the room that caused me to advise moving everything to the far wall. After all, we live in a world where non-metallic fiber-optic cable magnetically attracts backhoes.

Re:This guy is right, but if you can't move...

[SEWilco]

Big solid mass... rubber tires..

OK, so rent a small truck, drive it into the server room, and move all the systems into the truck for the duration. I'm sure any contractor with jackhammers can provide an entryway into the server room.

Re:This guy is right, but if you can't move...

[Louis_Wu]

Walls will carry the vibration, so I would stay away from them.

There is one other thing you can do that no one has suggested yet: put everything on a BIG solid mass, like a cube of steel. Why? Mass by itself 'damps' vibration. The equations of vibration point out that the amplitude of vibration can be reduced with straight damping (foam rubber and the like), or with a huge mass.

The reason the mass works is that the vibratory waves need a whole lot of energy to move a very large mass an appreciable distance, and so for any vibrations which don't register on the Richter scale (earthquake measurement system, I'm in California :) the energy in the vibration will only move that big mass a very small distance quite softly. And that small distance isn't critical to your hard drives.

This is the second order linear differential equation which describes most vibration situations. (Most - for one idealized point mass, a single linear spring, and a single linear damper. Seems quite limited, but most vibration can be described in this way quite accurately. I love approximation.)

m * a + c * v + k * x = F(t)

m = mass (the thing which is shaking)
c = damping coefficient (foam rubber)
k = spring constant (relation between the force applied and the distance the spring moves
F(t) = equation describing the action of the force over time

d^2 x
------ = a
d t^2

= the acceleration felt, a function of time

d x
---- = v
d t

= the velocity the mass moves at, a function of time

For the same force, the jackhammer crunching away all day long, a larger mass reduces the acceleration. 'm' goes up, 'a' goes down, simple algebra.

See if you can get a big solid chunk of mass to put everything on top of. But be careful to get something which can't shift internally, it will move more than a single block of the same size will. Maybe a big old steel desk. Whatever you find, I would put rubber cushions between your PCs and the big mass, for more insulation.

Good luck, and backup. :)

Louis Wu

"One of life's hardest lessons is that life's lessons are hard to learn."

the obvious answer?

[Jose]

move them.

Seriously. If the information on those drives are at all important, then you should either move them to the other side of the lab, or out of that room (cooling maybe a factor if they leave the room).

Re:Opposing-Phase Cancellation

[wazza]

Yah, all well and good, but it won't do anything for the real killer in this case - the transmitted vibration that conducts through the solid parts of the room, via the walls, floor, and desks to the computer & drives themselves. No amount of air-flapping on the part of 180 degree out of phase sound waves is going to stop that energy...

Opposing-Phase Cancellation

[SEWilco]

What, nobody has suggested the high-tech brute-force method? Have a microphone next to the wall, run it through an appropriate delay, and feed the signal to speakers which are between the wall and the disk drives. Delay the audio signal just enough for the original sound to arrive at the speakers exactly out of phase with the amplified version which the speakers are creating. Thus the speakers are creating a noise which is exactly opposite to the jackhammer noise. This is how the active noise-canceling headphones work, but it's a lot easier to engineer it for headphones.

This requires an audio system able to generate as much power as the jackhammer noise, and speakers which can withstand generating that sound.

If you are able to do this audio engineering job, I'd like to see the explanation for justifying a "Spinal Tap" quality audio system.

Re:Opposing-Phase Cancellation

[CharlieG]

You mean something like this?
Those shakers are nothing but BIG stiff air or water cooled speakers - They typically start at around 10 KILOWATS and go up from there. One of the systems I ran was 23 KVA, and the other was a tad over 100 KVA. I had the biggest amps on the block

Linux Jackhammer

[SEWilco]

Actually, my first thought when I saw the headline was that for some reason someone was putting a computer on a jackhammer and wanted to include a disk drive. I suppose a balancing, jumping jackhammer would make for an interesting fighting robot...

Closed Cell Foam

[remande]

I'd go to the nearest camping gear outfitter and ask for some closed-cell foam sleeping bag pads. Don't get the open-cell (looks like egg cartons), or the expensive self-inflating ones. Closed cell pads are about 1/2 to 3/4 inches thick, and they don't let air out when you squeeze them.

One nice thing about the closed-cell foam is that it can be cut, so one pad can handle several pieces of hardware.

One problem with them is that they are effective insulators--this is bad for anything that vents out the bottom.

Finally, and just for the sake of argument, I'd (gently) topple any towers--lay everything horizontally.

Re:Closed Cell Foam

[eufaula]

tilting them may not be a good idea if they are 10k scsi drives of any age. a tech at WD told me that as the drives spin over time they cut a minor groove in the spindle & bearings and seat themselves in this groove. if the drives are put in another position it could put stresses on them in a different direction resulting in damage to the drives. dont know if this is still applicable but it might be worth checking into. scsi drives arent cheap.....

Look at these folks

[CharlieG]

Check out EAR

They make all kinds of vibration control stuff - good for low amplitude stuff like you are seeing

Remember one important thing, a poorly designed vibration damper can make things MUCH worse! If the resonant frequency of the damper happens to fall near the fundamental frequency of the vibration, you will get amplification, NOT reduction! Worse yet, if those frequencies happen to be near the critical (aka resonant) frequencies of your hard drives. BTW the greater the damping over the longer the bandwidth, the larger the amplification

These guys offer a bunch of information on vibration and shock. I took Wayne's course at his old company back when I was doing vibration testing for a living - They were the only guys doing vibration testing courses in the early 80s

foam

[Zurk]

use the foam from packing boxes and put the SCSI drives on em with at least 1/4 to 1/2 inch of foam between the drives and a hard surface. should protect em nicely. use the soft spongy foam not the hard one. make sure you have enough ventilation/fans - SCSI drives (specially 10K RPM or more) ones get hot really fast...specially when encased in foam/insulation. i've lost drives which were completely off so shutting them down wont prevent vibration from killing em. foam will.

Suspend and float

[coyote-san]

Several people have already mentioned part of this approach, but not combined it.

1) Suspend a steady platform with bungee cords, ropes, whatever. It's far more important for it to be flexible than stretchy. You probably want to attach a few cords on the bottom to stop swinging - these should be stretchy.

2) Add extra mass to this platform - something like a layer of bricks. This will put the suspension cords under more tension (which allows them to transmit more vibrational energy), but the extra mass of the system should decrease the motion seen.

3) On top of this platform, put the partly inflated inner tube mentioned elsewhere. This platform holds the computers.

This is more complex than a single suspension system, but a single system will still transmit some key harmonic frequencies. But it's unlikely that two independent systems will share harmonics so there should be very little energy transmitted into the disks.

Sand

[lizrd]

Sandbags are great for eliminating vabrations. Most of the other posters on this thread have mentioned using something massive (like steel or granite) or something soft (like rubber or foam) to isolate your equipment from the vibrations. Sandbags have both qualities and are cheap as dirt too [ok, bad pun, couldn't help it]. Only thing to be careful of is making sure that your floor will support several hundred pounds of sand.

OT: turntables

[dave-fu]

Even better (in a solid environment)? Unengraved headstones.
No, wait. That fad died out (no pun intended) a decade ago. Nevermind.

Use rubberbands

[Jart]

Hang the drive, or the whole case, from the ceiling by rubberbands/bungees/surgical-rubber-tubing (say, 3 feet or more in length). Damps that vibration right out. Cheap too.

Easy

[sulli]

Don't jackhammer them!

Unless, of course, your real question is this previous Ask Slashdot.

cheap 'n cheerful solution

[relliker]

mount soft shock absorbers at each corner of a square piece of thick chipboard and strap your server on to it. Better than nothing and I used it successfully to mount desktops onboard ships although the design was somewhat more scientific than chipboard!

better safe than sorry.

[krismon]

move it all out of the area. move yourself out of the area, do your work in the hallway or outside if necessary. I'd call OSHA too... At the very least ask for a helmet.. I'm sure the guy with the jackhammer has one.

Re:better safe than sorry.

[Team Vogon]

OSHA? WHY? Are you just trying to create trouble for the contractor doing the work? OSHA won't help with this problem.

Worry about building first...

[human bean]

If there is enough vibration around to kill a properly mounted hard disc, you might want to worry about the mechanical and structural of the building. Most buildings I know don't come with a vibration rating.

Vibration is one of the worst things for hard disc drives, as the moments repeat themselves. Most G specs for drives are for a one-time shock. Disc drive suceptibility also depends greatly upon the orientation of the drive to the shock as well. Drives ae USUALLY (may vary by drive construction...) much less sensitive when the shock in in the same plane as the platters.

If this is a rack-mounted installation, try industrial equipment isolator pads. Little round things that go between the bottom of the rack and the floor. For desktop or similar, see if you can find an old wavepad from underneath a typerwriter (don't worry, son, look in a museum...) or a half-inch pad of Sorbothane (Costly, ouch....)

You're running tape backups, right?

[MeowMeow Jones]

Not trying to be a jerk, but that should be step number one if you're worried about hard-drives going.

Trolls throughout history:

It depends..

[cmowire]

It depends, of course, on how long it has been since your last backup and weather there is money in your budget for replacement drives. ;)

I mean, if there's a lot of vibration transmitted through the building structure, you are going to have a lot more to wory about than just the drives having a headcrash.

Jackhammers

[annielaurie]

While you're dealing with the vibrations, be sure to watch out for the dust -- where you've got one, there's a good chance you'll be dealing with the other.

I wouldn't try to protect the systems in any way -- just keep an eye on their outside cases and be prepared to clean a little more often. I neglected this in an at-home machine several years back while some wallboard was being fixed, and what I found inside after the work was done was a bit alarming. If I'd just dusted the case often with a clean cloth, I could have kept a lot of that dust away from the components.

I hope the construction goes away soon. It's not much fun.
Annie

*NOT* Anti-static

[wizzy403]

Just be sure that you do *NOT* use anti-static foam. It's conductive :P

Shock absorbing enclosure...

[wizzy403]

Well, you could pick up a shock-absorbing rack. They're expensive as hell, but if this jackhammering is going to be going on for a while (hope you have earplugs!) then it may be worth your while.

Here's one url:
http://www.martindaleassoc.com/its/4xpcmenc.htm

You can probably find more thru google or av. Meantime, get those puppies as far away from the vibs as possible. If you can power the drives off , all the better. It may not totally save them, but hard drives can take a lot more shock when stopped than when running.

Antinoise systems!!!

[sofar]

OK, here's how it works: a small chip analyzes incoming vibrations and sends out a sound signal which is a negative mirror image of the original sound, just at the right phase.

Here's where you can get it: NCTI

Unfortunataly they only sell small consumer electronic devices, so I guess you'd have to count
the number of disks you have, buy 1 antinoise headset for every disk, put the headsets on the disks, and off you go!!!

Couldn't be more simple than that (and from only $39, its a steal!!!)

Re:better safe than sorry. (OT)

[Team Vogon]

Since when does "helmet" mean ear protection? I would think that a "hard hat" would be closer to a "helmet" than ear protection.

Recap,
helmet -- protects head (i.e. Hockey Helmet)
hard hard -- protects head (i.e Used in Construction)
ear protection -- protects ears (i.e ear plugs or similar item)

Therefore helmet=hardhat which would most likely mean that hardhat or helmet does not equal ear protection.

Back in the day...

[queenb**ch]

I used to mess with holograms. We would suspend the platform on rubber balls (balloons for small objects). You know the same red ones you used to play dodge ball with. They will damp virutally all vibration and support an amazing amount of weight.

Build a plywood platform big enough to hold your rack and to sit off the floor with the equipment on in. Put the balls under the rack platform. Presto change-o and you are done.

You'd be surprised how much weight those cheesy playground balls will take under these circumstances and how well they dampen vibration. We once did a hologram of a lifesize bronze statue which weighed in at just over 1800 lbs. using this technique.