[mythtv-users] Software RAID (was: Where are those new 1TB drives?)

matthew.garman at gmail.com matthew.garman at gmail.com
Fri Mar 9 13:40:00 UTC 2007


On Fri, Mar 09, 2007 at 11:35:22AM +0000, Matthew McClement wrote:
> I've always sized my supplies based on the total *max* draw of all
> the drives combined. This is not the figure on the drives
> themselves, you usually have to dig around the spec sheets for
> this figure.

And the max power draw almost always occurs when you power on the
machine.  IIRC, startup power for a drive can be on the order of 30
watts, where regular running is maybe 10.  So if you have 10 drives,
and try to start them all at once, you'll have an instant 300 watt
demand, but steady-state operation is only about 100 W.

That is one nice thing about the expensive hardware RAID cards: they
usually have an option to specify spin-up delay on a per-drive
basis.  Theoretically you could power one drive at a time, and keep
your PSU load reasonable.

Matt



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