Re: [ANNOUNCE] udev 0.1 release

Richard B. Johnson
2003-04-11T20:34:34Z

On Fri, 11 Apr 2003, Mike Dresser wrote:

> On Fri, 11 Apr 2003, Chris Hanson wrote:
>
> > Using a tree (what you are calling massively parallel) for
> > distribution produces a uniform voltage drop for all of the devices,
> > and has a better worst-case voltage drop than a serial chaining
> > distribution. The serial chain has different voltage drops for each
> > pair of disks, depending on how far down the chain they are, but the
> > worst case is very bad.
> >
>
> I do wonder how we're going to run the 46KW of power (Assuming these
> drives pull similar to the drive i just checked) down the line.
>
> Should we use solid copper bars in a bus setup? You'll be pulling 2000
> amps off the 5v, and 3000 off the 12V. We may wish to rethink the method
> of hooking up our 46000 watt power supply. I suspect a bus may be a
> better way, and probably easier to setup and maintain.
>
> And much more fun when you drop a screwdriver across it.
>
> Mike

Well the "real-world" parallels at a much higher voltage. You
probably want a single power supply per drive, which eliminates
any single-point failure problems and allows you to use standard
stuff. To keep the heat-load down, you need to distribute the
drives over several large racks anyway. That allows you to get
perhaps 5 kW per rack if you use 9 racks so things are more
reasonable.

Cheers,
Dick Johnson
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