From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753229Ab3DOKAQ (ORCPT ); Mon, 15 Apr 2013 06:00:16 -0400 Received: from plane.gmane.org ([80.91.229.3]:42961 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274Ab3DOKAO (ORCPT ); Mon, 15 Apr 2013 06:00:14 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: "lkml@tigusoft.pl" Subject: Very poor latency when using hard drive (raid1) Date: Mon, 15 Apr 2013 11:59:59 +0200 Organization: tigusoft.pl Message-ID: Reply-To: lkml@tigusoft.pl Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: bolobolo1.torservers.net User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20121215 Icedove/3.0.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are 2 hard drives (normal, magnetic) in software raid 1 on 3.2.41 kernel. When I write into them e.g. using dd from /dev/zero to a local file (ext4 on default settings), running 2 dd at once (writing two files) it starves all other programs that try to use the disk. Running ls on any directory on same disk (same fs btw), takes over half minute to execute, same for any other disk touching action. Did anyone seen such problem, where too look, what to test? What could solve it (other then ionice on applications that I expect to use hard drive)?