From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Berra Subject: Re: Raid-10 mount at startup always has problem Date: Sat, 27 Oct 2007 09:50:55 +0200 Message-ID: <20071027075054.GA12053@percy.comedia.it> References: <46D49F1A.7030409@tmr.com> <46E4A39C.8040509@amfes.com> <46E4A5F0.9090407@sauce.co.nz> <46E4A7C3.1040902@amfes.com> <471F5542.3020504@amfes.com> <471FA485.6010705@tmr.com> <47202D17.3040000@amfes.com> <1193294406.10336.76.camel@firewall.xsintricity.com> <20071026091513.GB32550@percy.comedia.it> <1193426793.10336.302.camel@firewall.xsintricity.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Content-Disposition: inline In-Reply-To: <1193426793.10336.302.camel@firewall.xsintricity.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, Oct 26, 2007 at 03:26:33PM -0400, Doug Ledford wrote: >On Fri, 2007-10-26 at 11:15 +0200, Luca Berra wrote: >> On Thu, Oct 25, 2007 at 02:40:06AM -0400, Doug Ledford wrote: >> >The partition table is the single, (mostly) universally recognized >> >arbiter of what possible data might be on the disk. Having a partition >> >table may not make mdadm recognize the md superblock any better, but it >> >keeps all that other stuff from even trying to access data that it >> >doesn't have a need to access and prevents random luck from turning your >> >day bad. >> on a pc maybe, but that is 20 years old design. > >So? Unix is 35+ year old design, I suppose you want to switch to Vista >then? unix is a 35+ year old design that evolved in time, some ideas were kept, some ditched. >> partition table design is limited because it is still based on C/H/S, >> which do not exist anymore. >> Put a partition table on a big storage, say a DMX, and enjoy a 20% >> performance decrease. > >Because you didn't stripe align the partition, your bad. :) by default fdisk misalignes partition tables and aligning them is more complex than just doing without. >> >Oh, and let's not go into what can happen if you're talking about a dual >> >boot machine and what Windows might do to the disk if it doesn't think >> >the disk space is already spoken for by a linux partition. >> Why the hell should the existance of windows limit the possibility of >> linux working properly. > >Linux works properly with a partition table, so this is a specious >statement. It should also work properly without one. >> If i have a pc that dualboots windows i will take care of using the >> common denominator of a partition table, if it is my big server i will >> probably not. since it won't boot anything else than Linux. > >Doesn't really gain you anything, but your choice. Besides, the >question wasn't "why shouldn't Luca Berra use whole disk devices", it >was why I don't recommend using whole disk devices, and my >recommendation wasn't based in the least bit upon a single person's use >scenario. If i am the only person in the world that believes partition tables should not be required then i'll shut up. >> On the opposite, i once inserted an mmc memory card, which had been >> initialized on my mobile phone, into the mmc slot of my laptop, and was >> faced with a load of error about mmcblk0 having an invalid partition >> table. > >So? The messages are just informative, feel free to ignore them. but did not anaconda propose to wipe unpartitioned disks? >The phone dictates the format, only a moron would say otherwise. But, >then again, the phone doesn't care about interoperability and many other >issues on memory cards that it thinks it owns, so only a moron would >argue that because a phone doesn't use a partition table that nothing >else in the computer realm needs to either. i don't count myself as a moron, what i am trying to say is that partition tables are one way of organizing disk space, not the only one. >> >Anyway, I happen to *like* the idea of using full disk devices, but the >> >reality is that the md subsystem doesn't have exclusive ownership of the >> >disks at all times, and without that it really needs to stake a claim on >> >the space instead of leaving things to chance IMO. >> Start removing the partition detection code from the blasted kernel and >> move it to userspace, which is already in place, but it is not the >> default. > >Which just moves where the work is done, not what work needs to be done. and also permits to decide if it hat to be done or not. >It's a change for no benefit and a waste of time. the waste of time was having to put code in mdadm to undo partition detection on component devices, where partition detection should not have taken place. -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \