Re: Crash with Z77 chipset

[Robert Hancock <hancockrwd@gmail.com>]

On 12/18/2012 02:51 AM, Andrius Narbutas wrote:
> On 2012.12.18 05:41, Robert Hancock wrote:
>> My first thought would be that a power problem is a possibility. These
>> kinds of setups with multiple HDs in a RAID setup are known to cause
>> these issues in some cases if the PSU isn't adequate.
>
> I do not think PSU is a problem, because:
> 1) All hard disks combined draw less energy than loaded CPU, even at
> heavy load (from HDD datasheet: "Read/Write: 6.80 Watts; Idle    6.10
> Watts" - difference is 0.7W per HDD, so < 3W combined, CPU draws ~40W
> when loaded, compared to idle). Loading CPU/RAM to max does not crash
> system at all

The CPU has a voltage regulator in front of it which can compensate for 
dips in the input voltage. The disks don't. The wattage figures don't 
necessarily account for short-duration power draw peaks. And depending 
on how the drives are hooked up, especially if they are all on one 
cable, they can potentially see a problematic voltage drop.

> 2) I'm planning power supplies at 2x needed power (you know, all those
> "Chinese Watt" system is unreliable). Anyway, should be more than enough
> for whole system (and CPU is almost at idle when creating filesystem, so
> load on PSU is very low - should be < 70W - that's almost nothing on
> 560W PSU, even counting "Chinese Watt" coefficient)
> 3) If PSU is fault - why it fails at exact the same place? Most of
> hardware failures have some "random" factor - you get segfaults at
> random places from faulty RAM, crashes from dying PSU when doing random
> tasks... But now it fails at exactly the same place (when using the same
> kernel)
> 4) Let's say PSU is faulty. Then how comes, that with 3.6.10 kernel i
> still have control over system (when it crashes) - so only disk
> subsystem fails? Because it has only one 12V rail - you cannot
> disconnect disks from system, without killing motherboard power too. But
> after crash i still can do `ssh root@deadhost 'echo b >
> /proc/sysrq-trigger'` - so system is alive and working well (just disks
> are dead)
>
> I could imagine that motherboard itself is faulty (well, interesting
> anyway - why it fails only on heavy I/O load), so i will try to get
> Windows Server installed to check if that will work.