Partman manual configuration?

[Tom H]

On Fri, Aug 20, 2010 at 9:35 AM, Peter Smith
<peter.smith3882100 at gmail.com> wrote:
>
> I am installing Ubuntu 10.04 with the ubuntu-10.04-alternate-i386 CD
> as i need to configure an encrypted root volume without LVM. The disk
> is an Intel X25-M SSD so the partitions needs to be aligned, i
> configure language and keyboard settings, then i activate another
> console with ALT+F2 and use fdisk to partition the disk correctly. The
> console is closed and i continue with the installation on ALT+F1.
> After a few configuration steps partman is loaded by the installer, i
> choose "Manual" and the partitions created earlier with fdisk are
> shown. Now my problem is that dm-crypt needs to be aligned also by
> setting a custom LUKS "Payload offset" this is not possible from
> within partman and if i try to configure LUKS in another console
> before partman is loaded, the volume is not detected when partman is
> started. The custom LUKS "Payload offset" can be created with the
> command "cryptsetup luksFormat --align-payload=VALUE". Also the
> filesystem needs to be aligned, but this is not possible from within
> Partman either.
> Does anybody have any suggestions on how to solve this problem? Is it
> possible to disable partman under the installation?

AFAIK, the only way to format a drive precisely is to use fdisk or
parted in another vt and return to the installer.

I've never used cryptsetup/luksFormat but I couldn't understand from
your email why you needed to use an offset for them if you'd already
offset the partition so I looked at the man page.

Both take <device> as an argument so it seems to me that you don't
need to adjust the alignment after you've done so with fdisk.

Furthermore, the man page also has "--align-payload=value --> Align
payload at a boundary of value 512-byte sectors. This option is
relevant for luksFormat. If your block device lives on a RAID it is
useful to align the filesystem at full stripe boundaries so it can
take advantage of the RAID's geometry..." which seems to further
confirm that you can just encrypt your already-properly-aligned
partition.