On Mon, Mar 08, 2010 at 10:18:27AM -0500, Martin K. Petersen wrote: > >>>>> "Tejun" == Tejun Heo <tj@xxxxxxxxxx> writes: > 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? Yes, you're right. (IMHO our goal should be to minimize number of places where anything depends on partition type.) > Tejun> Reportedly, commonly used partitioners aren't ready to handle > Tejun> drives larger than 2 TiB in any configuration and alignment isn't The limit is specific for DOS partition table (with 512-byte log. sectors), but for example GPT uses 64-bit LBA. I believe that our partitioning tools don't introduce any other restriction. > 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. small summary: - libblkid provides unified API to topology information, it supports: - ioctls (kernel >= 2.6.32) - sysfs (kernel >= 2.6.31) - stripe chunk size and stripe width for DM, MD. LVM and evms on old kernels - libparted and fdisk are linked against libblkid - fdisk supports 4KiB logical sector size (util-linux-ng >= 2.15 - fdisk supports 4KiB physical sector size (util-linux-ng >= 2.17) - fdisk uses 1MiB alignment (or more if optimal I/O size is bigger) and alignment_offset for all partitions in non-DOS mode (util-linux-ng >= 2.17.1) - parted supports 4KiB physical sector size - parted uses 1MiB alignment for disks with unknown topology, disks with topology information are aligned to optimal (or minimum) I/O size (parted >= 2.1) - EFI GPT code in the kernel has been updated to works properly with 4KiB sectors (kernel >= 2.6.33) - mkfs.{ext,xfs,gfs2,ocfs2} have been update to work properly with topology information, mkfs.{ext,xfs} are linked against libblkid for compatibility with old kernel (for stripe chunk size / width) - Fedora-13/RHEL6 installer uses libparted with 4KiB support - alignment_offset & 4KiB support is planned for LUKS (cryptsetup) > 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. yes, util-linux-ng 2.17.1, fdisk -c Note that non-DOS mode will be default in the next major util-linux-ng release. Karel -- Karel Zak <kzak@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
