Re: Lots of con-current I/O = resets SATA link? (2.6.25.10)

[Justin Piszcz]

On Mon, 7 Jul 2008, Mattias Wadenstein wrote:

> On Sat, 5 Jul 2008, Justin Piszcz wrote:
>
> > On Sat, 5 Jul 2008, Robert Hancock wrote:
> >
> > > Justin Piszcz wrote:
> > > > > Can you post your dmesg from bootup with the controller/drive detection?
> > >
> > > So you've got 6 drives in the machine. Intel chipsets normally seem pretty 
> > > robust with AHCI.
> > >
> > > Are you certain that your machine has enough power to run all those drives 
> > > properly? We've seen in a number of cases that power fluctuations or noise 
> > > can cause these kinds of errors.
> >
> > I have a 650watt PSU (nice antec one) and the power draw of the box is 
> > ~148watts w/ veliciraptors, ~250 when fully load all 4 cores + all 12 disks 
> > writing.  I have turned off the irqbalance daemon and I am going to see if 
> > the problem re-occurs.
>
> Looking at the sum wattage number is really misleading for this. You need to 
> dig out the specs for how many amps it can provide on the different voltages 
> (5 and 12 volts). In particular, many modern PSUs have several separate 12V 
> rails, where one (or more, some have the 12V supply split into 3 or 4 parts!) 
> is used for CPU and GFX card power and usually only one is available for 
> disks.
>
> You can also have plenty of 12V left but run out of 5V, or the other way 
> around. I've spent quite some time trying to find a PSU that would handle 18 
> disks without costing too much. The splitting of the 12V power into separate 
> rails and a general lack of 5V compared to what the disks need according to 
> their specs just made it difficult, and I ended up bonding two PSUs together 
> (linking the ground together with some custom cabling) to get a stable 
> machine again.
>
> /Mattias Wadenstein

Good info here indeed but for my case it does not apply.  I used to have 
Raptor150s (12 of them on the same host) the ONLY thing that changed was 
the drives themselves.  And it used to use 150-250 watts (the 3.5" suck up 
a lot more power) the power cables are also exactly the same as they were 
on the Raptor 150s and I never had any issues.

I have two hosts, pretty much idential, I use the Antec TruePower Trio 650 
in each of them.

http://www.antec.com/us/productDetails.php?ProdID=23650

Justin.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/