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4kB Sector disk boot support


Make booting from disks with a 4kB sector size work on UEFI machines.


Current status

  • Targeted release: Fedora 15
  • Last updated: 2010-12-02
  • Percentage of completion: 100%

Detailed Description

Most rotational media has a sector size of 512 bytes. Disks exist with a sector size of 4096 bytes. Some day you may even be able to buy one. UEFI machines should be able to boot from them.

Benefit to Fedora

Hardware enablement.


Several things are needed here:

  • kernel has to support such disks
  • parted has to support such disks
  • efibootmgr has to be able to create nvram aliases for such disks
  • grub needs to be able to read filesystems on such disks

Test Plan


  • Get a UEFI machine
  • Get a disk with 4kB sectors
  • Install to the disk
  • reboot

UEFI-capable systems are available on the market, and 4kB disks from a number of vendors under NDA. Those with access to such systems are actively solicited to perform testing. We have very limited hardware access, which hampers the debugging effort.

  • Architectures:

X86 X86_64

User Experience

Significantly similar to that of today. To the user, this should appear exactly like booting from a more common 512b-per-sector disk.


Vendor support in hardware

Contingency Plan



Release Notes

  • 4kB sector size disks are not yet widely available and the user impact is negligible, so no release note is needed beyond "we support booting 4kB sector disks in UEFI environments"

Comments and Discussion