From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267988AbUHNDjY (ORCPT ); Fri, 13 Aug 2004 23:39:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268005AbUHNDjY (ORCPT ); Fri, 13 Aug 2004 23:39:24 -0400 Received: from rrcs-central-24-123-144-118.biz.rr.com ([24.123.144.118]:25456 "EHLO zso-proxy.zeusinc.com") by vger.kernel.org with ESMTP id S267988AbUHNDjW (ORCPT ); Fri, 13 Aug 2004 23:39:22 -0400 Subject: RE: High CPU usage (up to server hang) under heavy I/O load From: Tom Sightler To: Sylvain COUTANT Cc: "'Matt Domsch'" , Linux-Kernel In-Reply-To: <20040813154737.7DCC12FC2C@illicom.com> References: <20040813154737.7DCC12FC2C@illicom.com> Content-Type: text/plain Message-Id: <1092454748.3816.11.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Fri, 13 Aug 2004 23:39:09 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2004-08-13 at 11:46, Sylvain COUTANT wrote: > Hello Matt, > > > Which server please? > > PE 2600 manufactured in June with latest PC BIOS and SCSI (PERC4/DI) > BIOS/Firmware. We also tried downgrading to the previous release (as we have > another PE2600 which runs fine with them) but it didn't do. What driver are you using for the PERC? We have a Dell 1750 with a PERC/4Di which uses the megaraid driver under RHEL 3 and it has this same problem, but only when writing to drives connected to PERC controller. The system also has a Qlogic 2312 card connected to a EMC CX400 storage controller and performance to this device is fine, even if I setup and LUN on a single ATA disk. During heavy writes to the drives attached to the PERC4/Di the system becomes practically unusable. I've been wanting to try the 'megaraid2' driver to see if this gets rid of the issue but I haven't been able to try that yet. We have some older systems with PERC2/DC cards which also use the 'megaraid' driver but they don't seem to experience this issue so I'm a little suspicious that perhaps this driver simply doesn't work that well with the newer megaraid-like controllers. Later, Tom