Selective spin-up

Selective spin-up

[John Hendrikx]

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?

What's fun however is that if I press the power button again immediately 
after it powers down (while the drives are still half way spinned up), 
it will have enough power to spin up the disks all the way, and the 
system starts normally.  It runs rock solid after that.

Re: Selective spin-up

[Brad Campbell]

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?

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.

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.

Brad
-- 
"Human beings, who are almost unique in having the ability
to learn from the experience of others, are also remarkable
for their apparent disinclination to do so." -- Douglas Adams

Re: Selective spin-up

[Mark Hahn]

> > 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 

IMO, a many-disk server that tries to use normal non-server commodity parts
is pushing its luck.  the mass market just isn't friendly to >=8 disks in 
a box, either in terms of power, mounting, controllers, etc.  unfortunately,
once people start to "serverize" the hardware, it's easy to get carried away
into the gold-plated realm of FC sans and $20/GB end prices...

> > 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?

this can be implemented in various ways.  it's fairly common for SCSI disks
to have a jumper which causes them to delay spinup depending on their SCSI id.
for SATA systems, I get the impression that the direction is not yet settled.
one direction is to delay spinup until the link (phy) is initialized.
another is for disks to power-on into standby (not spinning but active).
I guess the main issue is that during boot, the bios has to find bootable 
partitions, which is only possible by actually spinning up disks and reading 
from them.  presumably the bios can skip spinup for disks not in the boot
device list.

incidentally, SMART can report "spin up time", which might be useful in
diagnosing situations when you might have too many drives...

Re: Selective spin-up

[Ross Vandegrift]

On Sun, Jan 22, 2006 at 07:28:59PM -0500, Mark Hahn wrote:
> for SATA systems, I get the impression that the direction is not yet settled.

FWIW, one of the important advances from the SATA-II board was the
inclusion of staggered spin-up.  There's most info on the details at
sata-io.org.

I do not know how commonly implemented the feature is in devices that
claim to support SATA-II specifications.


-- 
Ross Vandegrift
ross@lug.udel.edu

"The good Christian should beware of mathematicians, and all those who
make empty prophecies. The danger already exists that the mathematicians
have made a covenant with the devil to darken the spirit and to confine
man in the bonds of Hell."
	--St. Augustine, De Genesi ad Litteram, Book II, xviii, 37

Re: Selective spin-up

[Mattias Wadenstein]

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