Partitions are misaligned when using GPT on disks w/ 4096 byte physical sectors

Also, note that the "partman/alignment=minimal" was just used as a test to see if it made any difference. I found this issue without using any special kernel command line option.

Also, I'm attaching the disk-recipe I used for the install.

Adding the OEM Priority task because this issue affects some of Canonical's OEM customer projects in which disk performance will be degraded and cause a poor user experience.

Also, I can make an image available that has the full preseeded install.

Could you post:

  /sys/block/sda/alignment_offset
  /sys/block/sda/queue/minimum_io_size
  /sys/block/sda/queue/optimal_io_size
  /sys/block/sda/queue/physical_block_size

@Colin:

Here is your requested info:

$ cat /sys/block/sda/alignment_offset
0
$ cat /sys/block/sda/queue/minimum_io_size
4096
$ cat /sys/block/sda/queue/optimal_io_size
0
$ cat /sys/block/sda/queue/physical_block_size
4096

Also note that this has been seen on both Dell and Lenovo hardware.

This upstream bug seems like it may be related: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=674894

This bug was fixed in the package partman-base - 158ubuntu1

---------------
partman-base (158ubuntu1) quantal; urgency=low

  * Resynchronise with Debian. Remaining changes:
    - Ubiquity integration: If PARTMAN_NO_COMMIT is set, then exit rather
      than running commit.d and finish.d scripts; add a partman-commit
      script; dump extra information to /var/lib/partman/snoop if
      PARTMAN_SNOOP is set; check for per-menu 'no_show_choices' file in
      ask_user and don't reshow the menu if it exists.
    - Don't skip over dmraid devices if the user chooses not to activate
      them.
    - If the only thing mounted on a disk is the installation medium and it
      uses more or less the whole disk, then silently exclude that disk; if
      the installation medium is mounted but doesn't use the whole disk,
      issue a warning that partitioning may be difficult; if anything else
      is mounted, offer to unmount it. partman/filter_mounted=false disables
      this.

partman-base (158) unstable; urgency=low

  * Permit non-cylinder alignment again on GPT (closes: #674894,
    LP: #1006894).

partman-base (157) unstable; urgency=low

  * Team upload

  [ Updated translations ]
  * Croatian (hr.po) by Tomislav Krznar
  * Portuguese (Brazil) (pt_BR.po) by Felipe Augusto van de Wiel (faw)
 -- Colin Watson <email address hidden> Mon, 02 Jul 2012 14:42:31 +0100

Hello Christopher, or anyone else affected,

Accepted partman-base into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/partman-base/153ubuntu5 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please change the bug tag from verification-needed to verification-done. If it does not, change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

For Precise, I tested this on both GPT style partition tables and PC MBR style partition tables. The GPT disks are now aligned. I detected no regressions in the MBR disks.

This bug was fixed in the package partman-base - 153ubuntu5

---------------
partman-base (153ubuntu5) precise-proposed; urgency=low

  * Permit non-cylinder alignment again on GPT (closes: #674894,
    LP: #1006894).
 -- Colin Watson <email address hidden> Mon, 02 Jul 2012 14:54:45 +0100

Does anyone have any clever approaches for install this updated udeb into a precise installer? Things I've tried:

* downloading and installing an updated deb in preseed/early_command fails since the postinst tries to run parted and it's too early to do so
* downloading and installing an updated deb in partman/early_command doesn't work since it runs it as a part of partman and thus runs partition twice
* expanding the package into the initrd and booting w/ that results in the old package (153ubuntu4) being installed over it.

Any other ideas? Thanks in advance.

Images in:
http://cdimages.ubuntu.com/ubuntu-server/precise/daily/current/
Have this updated partman-base.