From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262086AbVD1PAG (ORCPT ); Thu, 28 Apr 2005 11:00:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262087AbVD1PAG (ORCPT ); Thu, 28 Apr 2005 11:00:06 -0400 Received: from clock-tower.bc.nu ([81.2.110.250]:35535 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S262086AbVD1PAA (ORCPT ); Thu, 28 Apr 2005 11:00:00 -0400 Subject: Re: [Question] Does the kernel ignore errors writng to disk? From: Alan Cox To: mike.miller@hp.com Cc: Linux Kernel Mailing List , linux-scsi@vger.kernel.org, brace@hp.com In-Reply-To: <20050427184022.GA16129@beardog.cca.cpqcorp.net> References: <20050427184022.GA16129@beardog.cca.cpqcorp.net> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1114700283.24687.193.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Thu, 28 Apr 2005 15:58:08 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mer, 2005-04-27 at 19:40, mike.miller@hp.com wrote: > It looks like the OS/filesystem (ext2/3 and reiserfs) does not wait for for a successful completion. Is this assumption correct? Of course it doesn't. At 250 ops/second for a decent disk no OS waits for completions, all batch and asynchronously queue I/O. See man fsync and also O_DIRECT if you need specific "to disk" support. If you do that be aware that you must also turn write caching off on the IDE disk. I've repeatedly asked the "maintainer" of the IDE layer to do this automatically but gave up bothering long ago. Without that setting users are playing with fire quite honestly. The alternative with latest 2.6 stuff is to turn on Jens Axboe's barrier work which seems to give better performance on a drive new enough to have cache flush operations. Alan