From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: ATA 4 KiB sector issues. Date: Mon, 08 Mar 2010 10:18:27 -0500 Message-ID: References: <4B947393.2050002@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from rcsinet12.oracle.com ([148.87.113.124]:22190 "EHLO rcsinet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755185Ab0CHPUj (ORCPT ); Mon, 8 Mar 2010 10:20:39 -0500 In-Reply-To: <4B947393.2050002@kernel.org> (Tejun Heo's message of "Mon, 08 Mar 2010 12:48:35 +0900") Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: "linux-ide@vger.kernel.org" , lkml , Daniel Taylor , Jeff Garzik , Mark Lord , tytso@mit.edu, "H. Peter Anvin" , hirofumi@mail.parknet.co.jp, Andrew Morton , Alan Cox , irtiger@gmail.com, Matthew Wilcox , aschnell@suse.de, knikanth@suse.de, jdelvare@suse.de, Karel Zak , Jim Meyering >>>>> "Tejun" == Tejun Heo writes: Tejun> The [Windows Vista/7] partitioner seems to be using 1M as the Tejun> basic alignment unit and offsetting from there if explicitly Tejun> requested by the drive Yep. Tejun> Please note that hdparm is misreporting the alignment offset. It Tejun> should be reporting 512 instead of 256 for offset-by-one drives. Already fixed. Your hdparm must be old. Tejun> Partitioners maybe should only align partitions which will be Tejun> used by Linux and default to the traditional layout for others Tejun> while allowing explicit override. I don't think we take the partition type into account. Karel? Tejun> Reportedly, commonly used partitioners aren't ready to handle Tejun> drives larger than 2 TiB in any configuration and alignment isn't Tejun> done properly for drives with 4 KiB physical sectors. 4 KiB Tejun> logical sector support is broken in both the kernel Huh, what? My homedir is on a 4KiB LBS/PBS drive and has been for ~2 years. Tejun> (need more details and probably a whole section on partitioner Tejun> behaviors) I'm Cc:'ing Karel Zak and Jim Meyering who have been doing all the alignment work for fdisk and parted respectively. Karel, Jim: The full writeup is here: http://ata.wiki.kernel.org/index.php/ATA_4_KiB_sector_issues It'd be great if you guys could share what you have been doing to the tooling. Tejun> Unfortunately, the transition to 4 KiB sector size, physical only Tejun> or logical too, is looking fairly ugly. Hopefully, a reasonable Tejun> solution can be reached in not too distant future but even with Tejun> all the software side updated, it looks like it's gonna cause Tejun> significant amount of confusion and frustration. With regards to XP compatibility I don't think we should go too much out of our way to accommodate it. XP has been disowned by its master and I think virtualization will take care of the rest. FWIW, recent fdisk has a command line flag that will enable/disable DOS compatible layout. -- Martin K. Petersen Oracle Linux Engineering