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Delaying Hard Drive Power Up?
Bamfarooni asks: "Does anyone know of a device that will delay
powering up your hard-drives (or other internal devices)? We're trying
to put a pile of IDE disks into a big disk server but the spin-up
power for these disks is about 3x the maximum operating current.
Rather than put in something really big like an 800W power supply, if
we could just put something in-line that delayed the power through
specific connectors for ~1 second, then we could mange with the
built-in power supplies we already have." An interesting thought,
but wouldn't the BIOS need to be aware of whatever delay is introduced?
Otherwise it may interpret the delay wrongly and think that the drives
on the IDE chain have timed out and are faulty.
Buying a larger power supply would be much more cost efficient than trying to devise some device that alternated current between hard drives.
There isn't any glory in such a hardware hack. There is just a lot of wasted time for a non-issue.
Just move them outside the box with their own power supply.
Seems a lot safer and easier than trying to 'fool' them.
Hogsback
If your power supply can't handle booting, it needs to be upgraded! That's like always having to have someone around to jump your car...it means something is underpowered and not working right. You might wanna try DUAL power supplies, instead of one MEGA power supply...it's how we support 12+ Ultra3 SCSI drives in one box in all of our servers ;)
I know you probably realize that SCSI does/can do this. But I also know that you're probably using IDE because SCSI drives of comparable size will be like twice the cost.
But, you might look into a hybrid solution by using SCSI-to-IDE converters. I'm not sure if the 'delay spinup' feature is dependent on the drive itself or just the SCSI Host Card, but if it's the SCSI card that does delayed spinup, you might be able to do this.
Something like this is what I'm thinking about. Of course, they charge $70 each adapter (which means per drive, too) -- though you may be able to get a better deal somewhere else.
Also, depending on OS, have you looked into a firewire solution? THey don't delay spinup, but you can use external power with them (via the drive or the hub/repeater).
Hilary Rosen's speech was about her love of money and her desire to roll around naked in a pile of money.
Some motherboards settings (including a crappy Gateway i was messing with yesterday) have a "harddisk predelay" that you can adjust a time period before it polls for harddrives.
Adjusting that setting higher would address that.
What not put the Drives in a separate box, with its own power supply that way you can start that box 10 seconds before the main CPU box....ATX tower case 350`400watt power supply fits/powers 8-12 drives $100...cheap and easy.
Power Corrupts,Absolute Power Corrupts Absolutely, leaving one person(group)in charge is absolutely corrupt.
Why not just use two or three 300 watt power supplies? A top quality 400 watt PSU is can be found for about $40-$60. Just get 2 for $80. Much cheaper than an 800w power supply (which doesnt even exist!)
:). Or, you could use an AT power supply, which doesn't need a motherboard in order to operate. Im not sure if the BIOS will recognize a drive that is already powered up, though?
I forget what pins... but if you short two of the pins on the ATX motherboard connector, it powers up. In theory all you would need to do is make sure the drives all power up at roughly the SAME time. This could be easily accomplished with a few bits of wire and a doorbell
Some older bioses used to be able to init the hard drives at a timed delay. This was due to the fact that the hard drive wouldnt spin up fast enough to be recognized. This is no longer a problem, and has been omitted from all modern bioses.
Finally, the timed spinup idea isn't really a good idea. If several hard drives spin down, and then all resume at the same time, it would overload the power supply, causing damage to the PSU, and most likely other (expensive) components along with it.
Long and short: Use 2+ power supplies, attach both of them to a doorbell (or case button, but those are usually too small to attach two pieces of wire), and they will both power up synchronously.
-- If you try to fail and succeed, which have you done? - Uli's moose
I would reccomend putting some drives in another case, but here's an alternate solution:
Get a housing that will hold a bunch of two-circuit switches, one for every two drives. Get a bunch of those little hdd power cable ends (male and female) and some Y-cables, one for every two drives. Get the switches as well. Put the switches between the power supply and the drives. When you power up, throw a switch and let one pair spin up, repeat until done. Set a boot password on the BIOS. Don't enter it until all drives are spun up. If it does IDE detection before the passworf prompt, just do a soft reset.
This is really dumb. Get another power supply, or get one of those nifty DEC StorageWorks towers from your nearest data center that's chucking them out the window.
The folks at PC Power and Cooling have this monster which, altough comprised of 2 separate hot-swappable 420W PSU's, is supposed to be able to deliver 840W peak.
Guess I'm imagining that old Versyss server taking up room downstairs... And I think its PS even has standard 4-pin molex connectors (although it still wouldn't work very well as the only supply in a new system, as it lacks either AT or ATX mobo power connectors.)
I had a similar problem with a standard case in which I stuffed a dual processor motherboard and eight peripherals. I simply connected five of the eight drives to a second power supply. Cheap and effective, it just means that I have a second power switch to flick, but since it happens about once a month that's not a big deal. On the other hand, the second power supply was ripped from another PC and sitting on top of the tower with the dangling cables it is indeed quite ugly and my wife hates it, although I like the extra cachet that exposed guts provide.
Any good electronics shop or catalog should have 120v relays with a preset delay on them (usually 5-20 seconds). I have several 5 second ones on a rack of AV gear where I work, ganged together so equipment turns on 0, 5 and 10 seconds after the switch is thrown.
They're pretty cheap ($20), and if you've got drives on a separate powersupply, hooking it up should be trivial.
BBK
SCSI does this automatically...drive spin delay can be totally disabled until a START UNIT command is issued from the controller, or set to delay spinup 12sec * SCSI ID.
Very handy for big arrays.
JWK
He'll tell you what you need in 2 words:
Big Caps
Put one on each the +5 and +12 volt rails going to your drives. Be sure they're charged and isolated from leakage before powering up the system.
You could do a 2 stage power-up for your system. 1st stage uses the regular switch on your powersupply and does nothing but charge up the caps. Second stage is when you actually apply power to the motherboard and all your drives inside. This would require a separate switch that could turn on/off all the +-5 and +-12 volt legs necessary. A few relays or solid-state relays would do nicely, perhaps a plain triac or SCR on each would do, but you'd need to do some reasearch on those. I haven't messed with them for some time now.
After you hit the 2nd switch, the drives would get the current they need from both the caps and the regular [underpowered] supply.
Of course this is all a bit more work than just getting another small powersupply for $15 or so like everyone else is suggesting -- but you asked the question.
Basically, on a cold boot, the system wouldn't start; you had to either disable the fast boot options in the BIOS or power up, wait 5 seconds and hit reset.
Rig some toggle switches on both power lines to each drive and have the operator manually turn on the drives as the machine is powering up.
Or do the right thing and go SCSI.
It's true that the Linux kernel will see drives that the BIOS did not detect, but it has to boot first. Obviously then, the drive with the bootloaded can not be on a delayed start - or you'd have to boot initially from other media.
Couldn't you just set the hard drive options in bios, and then not have to scan for it at first?
(this would probably work best for a non-booting drive)
Need a Catering Connection
Use SCR's at every drive with a Resistor/Capacitor to time the gate. Each drive down the line would have a longer Time Constant. A .3 to .5 voltage drop shouldnt cause any problems.
Use a couple of ordinary PC/AT power supplies just to power the drives. Run them up first, then hit the power on the main PC...
Alternatively, you could use some kind of delay circuit to switch the drives in sequence, finally pulling the orange "power good" line to +5v.
Wasn't the goal to make it so that he didn't need another power supply?
/humor
Be sure not to use excessive force while spinning up your tape drives, as you might stretch and tear the magnetic tape. This would most likely ruin the data stored on them.
1 tequila 2 tequila 3 tequila floor
If the multiple PC's are identical, Let someone reverse engineer a power supply. Most have a timer on the Power Good line. It times out after the supply is stable. A selection of delay caps for the various supplies should delay the startup of the machines. This way when the mains for the rack is turned on, the machines would boot up after various delays.
The truth shall set you free!