Ubuntu Installer borks up partitions?

Tom H tomh0665 at gmail.com
Tue Jul 9 11:47:12 UTC 2013


On Mon, Jul 8, 2013 at 5:07 AM, Sander Smeenk <ssmeenk at freshdot.net> wrote:
> Quoting Tom H (tomh0665 at gmail.com):


>> Reporting "I can't recreate the Ubuntu installer's disk layout without
>> using sfdisk and --force" is unlikely to be considered much of an
>> issue by anyone.
>
> Really?

Yes. File a bug and post the link here...


> Isn't you saying "i havent been able to use sfdisk [to recreate a broken
> partition table layout] without using --force" exactly what describes a
> problem ('issue') in the Ubuntu Installer partition layouts?

Where do Ubuntu's or util-linux's developers give you an assurance
that you'll be able to replicate with fdisk/sfdisk the partition
layout that the Ubuntu installer creates.

Using "--force" isn't an issue; the Ubuntu installer *might* be using
it too (or it might be using d-i's partman or parted or parted via
partman or something else). AFAIK "--force" is needed because sfdisk
unlike fdisk still cares about cylinders and emits warnings about it.
Furthermore it isn't unusual to force something. Fedora's Anaconda
installer uses "grub2-install --force" to install grub2 to a partition
if the user requests it and its user and test mailing lists are full
advice to use "--force" manually because that's the official (and
only) way to replicate what used to be more straightforward with
grub1. They may stop giving this advice at some point, either because
they will choose to concur with grub2 upstream or because EFI is
making embedding grub a prehistoric factoid.

So in the above case, it's not just some non-standard manipulation
like you want/need to do but a more or less standard setup that needs
"-force".


> The fact that you got used to hacking(!) your way through it, dumping
> partition tables to textfiles, manually changing boundaries to
> incorrect(!) values and forcing(!) a tool to write the broken layout to
> disk does not make this 'normal operation', it indicates a problem that
> should be fixed. Amiright?

No.

There's no hacking involved. This is a standard way of using sfdisk!

As long as the partitions aren't overlapping, there's nothing
inherently incorrect in the installer's partition layout. The
installer's developers might choose in the future to space out
partitions in the same way that fdisk does there's no way that anyone
can claim that the layout that the installer created for you is
incorrect/broken.


> So, thanks for confirming the problem with Ubuntu Installer partition
> tables, now let's focus on finding out how to report this / get this
> fixed.

Feel free to waste you time getting a non-problem fixed...

If anything, it's a bug in sfdisk but I doubt that upstream is unaware
of this problem. It's just that fdisk is getting more love than
sfdisk. Not only has it removed any reference to cylinders and heads
in fdisk (as seen in the Fedora output below; the Ubuntu fdisk output
still refers to them since it's using an older fdisk because of the
Debian freeze; their sfdisk outputs are similar) but it's also working
on gpt support.


FDISK output on Fedora

[root at box:~]# fdisk -l /dev/sdc

Disk /dev/sdc: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xacdbea63

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1            2048     8388607     4193280   83  Linux


FDISK output on Ubuntu

[root at box:~]# fdisk -l /dev/sdc

Disk /dev/sdc: 4294 MB, 4294967296 bytes
43 heads, 32 sectors/track, 6096 cylinders, total 8388608 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xacdbea63

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1            2048     8388607     4193280   83  Linux




More information about the ubuntu-users mailing list