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

[Justin Piszcz <jpiszcz@lucidpixels.com>]

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.