From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: Crash with Z77 chipset Date: Tue, 18 Dec 2012 21:36:51 -0600 Message-ID: <50D13653.3000708@gmail.com> References: <50CF5143.5020207@gmail.com> <50CFE5E3.9080003@gmail.com> <50D02E83.3090403@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ie0-f177.google.com ([209.85.223.177]:61155 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754071Ab2LSDmI (ORCPT ); Tue, 18 Dec 2012 22:42:08 -0500 Received: by mail-ie0-f177.google.com with SMTP id k13so2050186iea.22 for ; Tue, 18 Dec 2012 19:42:07 -0800 (PST) In-Reply-To: <50D02E83.3090403@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Andrius Narbutas Cc: linux-ide@vger.kernel.org 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.