From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Berra Subject: Re: Raid-10 mount at startup always has problem Date: Sun, 28 Oct 2007 14:37:44 +0100 Message-ID: <20071028133736.GA22861@percy.comedia.it> References: <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> <20071027075054.GA12053@percy.comedia.it> <1193518050.10336.343.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: <1193518050.10336.343.camel@firewall.xsintricity.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Sat, Oct 27, 2007 at 04:47:30PM -0400, Doug Ledford wrote: >On Sat, 2007-10-27 at 09:50 +0200, Luca Berra wrote: >> 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. > >BSD disk labels are still in use, SunOS disk labels are still in use, i am not a solaris expert, do they still use disk labels under vxvm? oh, by the way, disklabels do not support the partition type attribute. >partition tables are somewhat on the way out, but only because they are >being replaced by the new EFI disk partitioning method. The only place >where partitionless devices is common is in dedicated raid boxes where >the raid controller is the only thing that will *ever* see that disk. well i am more used to other os (HP, AIX) where lvm is the common mean of accessing disk devices .... >> by default fdisk misalignes partition tables >> and aligning them is more complex than just doing without. > >So. You really need to take the time and to understand the alignment of >the device because then and only then can you pass options to mke2fs to yes and i am not the only person in the world doing that. >> >Linux works properly with a partition table, so this is a specious >> >statement. >> It should also work properly without one. > >Most of the time it does. But those times where it can fail, the >failure is due to not taking the precautions necessary to prevent it: >aka labeling disk usage via some sort of partition table/disklabel/etc. I strongly disagree. the failure is badly designed software. >Did you stick your mmc card in there during the install of the OS? My laptop has a built-in mmc slot, so i sometimes leave a card plugged in. But the mmc thing was just an example, it is not that critical. >> 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. > >Using whole disk devices isn't a means of organizing space. It's a way >to get a rather miniscule amount of space back by *not* organizing the >space. if i am using, say lvm to organize disk space, a partition table is unnecessary to the organization, and it is natural not using them. >This whole argument seems to boil down to you wanting to perfectly >optimize your system for your use case which includes controlling the >environment enough that you know it's safe to not partition your disks, >where as I argue that although this works in controlled environments, it >is known to have failure modes in other environments, and I would be >totally remiss if I recommended to my customers that they should take >the risk that you can ignore because of your controlled environment >since I know a lot of my customers *don't* have a controlled environment >such as you do. The whole argument to me boils down to the fact that not having a partition table on a device is possible, and software that do not consider this eventuality is flawed, and recommnding to work-around flawed software is just digging your head in the sand. But i believe i did not convince you one ounce more than you convinced me, so i'll quit this thread which is getting too far. Regards, L. -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \