Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752793Ab0BQWCd (ORCPT ); Wed, 17 Feb 2010 17:02:33 -0500 Received: from dsl-67-204-24-19.acanac.net ([67.204.24.19]:49436 "EHLO emergent.ellipticsemi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751446Ab0BQWCb (ORCPT ); Wed, 17 Feb 2010 17:02:31 -0500 Date: Wed, 17 Feb 2010 16:37:41 -0500 From: Nick Bowler To: david@lang.hm Cc: Volker Armin Hemmann , Kyle Moffett , Rudy Zijlstra , Neil Brown , "Mr. James W. Laferriere" , Bill Davidsen , Michael Evans , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: Linux mdadm superblock question. Message-ID: <20100217213741.GA16938@emergent.ellipticsemi.com> Mail-Followup-To: david@lang.hm, Volker Armin Hemmann , Kyle Moffett , Rudy Zijlstra , Neil Brown , "Mr. James W. Laferriere" , Bill Davidsen , Michael Evans , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org References: <201002140251.59668.volkerarmin@googlemail.com> <20100217181016.GA14983@emergent.ellipticsemi.com> <201002171927.07051.volkerarmin@googlemail.com> <20100217183703.GA15446@emergent.ellipticsemi.com> <20100217185105.GA15614@emergent.ellipticsemi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Elliptic Technologies Inc. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1718 Lines: 43 On 13:17 Wed 17 Feb , david@lang.hm wrote: > On Wed, 17 Feb 2010, Nick Bowler wrote: > > > On 10:41 Wed 17 Feb , david@lang.hm wrote: > >> On Wed, 17 Feb 2010, Nick Bowler wrote: > >>> It takes about half a second for mdadm to assemble my root array, is > >>> that what you're referring to? > >>> > >>> I assume that kernel auto-assembly is no faster, although I've never > >>> used it. Regardless, half a second isn't very long to wait. > >> > >> If you are aiming for a 5-second boot time it's 10% of your total boot > >> time. That's a lot for a feature that's not needed. > > > > Only if the kernel auto-assembly takes zero time, which it obviously > > does not. > > the assembly time would probably be the same, but the initramfs being > proposed did not include that time either. This was the *only* time that was included. Quoting myself: > It takes about half a second for mdadm to assemble my root array I didn't make any claim about any other timings, since I have not made any measurements (I am not adding instrumentation code to my initramfs and rebooting the box just to do this, and my watch is not precise enough to measure the time spent in initramfs). After the kernel has loaded, but before init on my root fs is run, there are only three things that cause noticeable delays: * probing all the disks. * assembling the root array. * mounting the root filesystem. -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/