From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hermann Himmelbauer Subject: Re: Disk I/O stuck with KVM - no clue how to solve that Date: Sun, 7 Nov 2010 17:07:51 +0100 Message-ID: <201011071707.51508.dusty@qwer.tk> References: <201011051816.59032.dusty@qwer.tk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Stefan Hajnoczi Return-path: Received: from mx04.lb01.inode.at ([62.99.145.4]:43827 "EHLO mx.inode.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752634Ab0KGQH5 (ORCPT ); Sun, 7 Nov 2010 11:07:57 -0500 In-Reply-To: Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Am Samstag 06 November 2010 20:58:12 schrieb Stefan Hajnoczi: > On Fri, Nov 5, 2010 at 5:16 PM, Hermann Himmelbauer wrote: > > I experience strange disk I/O stucks on my Linux Host + Guest with KVM, > > which make the system (especially the guests) almost unusable. These > > stucks come periodically, e.g. every 2 to 10 seconds and last between 3 > > and sometimes over 120 seconds, which trigger kernel messages like this > > (on host and/or guest): > > > > INFO: task postgres:2195 blocked for more than 120 seconds > > The fact that this happens on the host too suggests there's an issue > with the host software/hardware and the VM is triggering it but not > the root cause. > > Does dmesg display any other suspicious messages? No, there's anything that can be seen via dmesg. I at first suspected the hardware, too. I can think of the following reasons: 1) Broken SATA cable / Harddisks - I changed some cables, no change, thus this is probably ruled out. I also can't see anything via S.M.A.R.T. Moreover, the problem is not bound to a specific device, instead it happens on sda - sdd, so I doubt it's harddisk related. 2) Broken Power Supply / Insufficient Power - I'd expect either a complete crash or some error messages in this case, so I'd rather rule that out. 3) Broken SATA-Controller - I cannot think of any way to check that, but I'd also expect some crashes or kernel messages. I flashed the board to the latest BIOS version, no change either. However, it seems no one except me seems to have this problem, so I'll buy a new, similar but different mainboard (Intel instead of Asus), hopefully this solves the problem. What do you think, any better idea? Anyway, thanks for your reply! Best Regards, Hermann -- hermann@qwer.tk GPG key ID: 299893C7 (on keyservers) FP: 0124 2584 8809 EF2A DBF9 4902 64B4 D16B 2998 93C7