On Sun, 22 Jan 2006, Brad Campbell wrote:
John Hendrikx wrote:
I recently extended my raid array with a 9th drive, and I find that the 300
watt PSU I use is insufficient to start the system. What happens is that I
activate the machine, the machine starts powering up for 3 seconds orso
(spinning all the hard drives up about half way) then power cuts out. I've
heard that it is possible to spin up disks one at a time or in groups, but
cannot find any such option in the BIOS (Asus A8N-E board). Any ideas?
And just in response to the original question, this is called "staggered
spin-up" and is usually a feature of larger raid/scsi controllers and
intelligent backplanes. Usually not found in cheap hardware.
I had a similar problem with a 480W PSU and my 15 drive array..
I looked for selective spinup and other hacks, but to be honest I figured
that even if the trip point is under spin up load only, I was running the PSU
too close to the wire to be comfortable.
I bought a 600W unit and re-wired it's dual 12V rails to do the job.. Problem
solved.
Heh, I just did this for an 18 drive machine too. Much better than the old
duct-taped 2 PSU "solution":
http://www.acc.umu.se/~maswan/bilder/20060117-Kryddis/
I also run a smart check every morning (6 days short 1 day long)
simultaneously on all drives to make sure the system behaves under load.
Do yourself a favour and grab a shiny new PSU.. I have 14 Drives hanging off
a 420W unit in my other box that behave perfectly..
Just look at the the 12V rail capacity on any PSU you choose and make sure it
will cope with the spool up load. I grabbed Maxtor's docs on these drives,
calculated the load for 15 drives and worked from there.. My practical
measurements came to within about 15% of the theoretical so the docs are not
to bad.
Don't forget to take a look at the 5V load too. The last batch of drives I
got for that machine was hitatchi sata drives which claims 1.3A in "max
r/w load". Lots of PSUs even with high W-ratings (600/800) have only 20 or
30A rated 5V load, and you want some left over for the rest of the system.
Now, if I could only get rid of these load-induced sata_sil (or whatever
it is) cold hangs everything would be awesome. :)
/Mattias Wadenstein
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