Messages in this thread | | | Subject | Re: ATA 4 KiB sector issues. | From | "Martin K. Petersen" <> | Date | Mon, 08 Mar 2010 10:18:27 -0500 |
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>>>>> "Tejun" == Tejun Heo <tj@kernel.org> 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
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