From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262398AbUEGB3q (ORCPT ); Thu, 6 May 2004 21:29:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262406AbUEGB3q (ORCPT ); Thu, 6 May 2004 21:29:46 -0400 Received: from mailgate2.mysql.com ([213.136.52.47]:10445 "EHLO mailgate.mysql.com") by vger.kernel.org with ESMTP id S262398AbUEGB3o (ORCPT ); Thu, 6 May 2004 21:29:44 -0400 Subject: Re: Random file I/O regressions in 2.6 From: Peter Zaitsev To: Nick Piggin Cc: Andrew Morton , alexeyk@mysql.com, linuxram@us.ibm.com, linux-kernel@vger.kernel.org, axboe@suse.de In-Reply-To: <409ACF04.8010805@yahoo.com.au> References: <200405022357.59415.alexeyk@mysql.com> <200405050301.32355.alexeyk@mysql.com> <20040504162037.6deccda4.akpm@osdl.org> <200405060204.51591.alexeyk@mysql.com> <20040506014307.1a97d23b.akpm@osdl.org> <1083867233.2420.29.camel@abyss.local> <20040506144933.1918317f.akpm@osdl.org> <409ACF04.8010805@yahoo.com.au> Content-Type: text/plain Organization: MySQL Message-Id: <1083893376.2420.194.camel@abyss.local> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Thu, 06 May 2004 18:29:37 -0700 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2004-05-06 at 16:49, Nick Piggin wrote: > > > > `nomtime' would be simpler and safer to implement, but not as nice. > > > > But we need those numbers first. I'll take a look. > > > > Can they use fdatasync? Does it do the right thing on Linux? Nick, You're right. fdatasync suppose to be solution in this case and actually test supports this mode as well as MySQL does :) On other hand if you rather use O_DSYNC it does not seems to work being mapped to O_SYNC. But the thing I'm mostly interested in is O_DIRECT. It seems to be the best solution for many database needs, especially used together with asynchronous IO. There is however no matching option which should not flush MetaData. -- Peter Zaitsev, Senior Support Engineer MySQL AB, www.mysql.com