Advanced filesystem option: boot flag issue

[orschiro]

Hi there,

Many thanks for these great developments of Antergos and Cnchi!

Last time I installed Antergos was back in 2012 and I was totally satisfied with it. Until yesterday when I accidentally broke my entire system due to a wrong option in an rsync backup script...

Thus time for a new, clean installation. I used the advanced option at the point of filesystem partitioning.

I used to use only three LVM partitions:

• Volgroup00/Arch
• Volgroup00/Home
• Volgroup00/Swap

Volgroup00/Arch was also the place of my /boot partitioning. However, with Cnchi .35 it is complaining that I don't have a boot partition set.

Is it possible to add an option in the Installer to manage the flags, i.e. being able to the boot flag to one of the LVM partitions?

As a workaround I created a new partition Volgroup00/Boot but would have preferred to stay with 3 partitions.

Warmly,

Robert

[karasu]

Hi,

Thanks for you kind words and your feedback. I'll check this because it should let you go on without a boot partition, but if I recall correctly there are some cases where we enforce a boot partition....

I'll look into it asap. Thanks!

[orschiro]

Thanks for looking into it. I am very pleased by the new installation. It was worth it!

[lots0logs]

We enforce a boot partition when using LVM because grub required it (at that time). I believe grub's LVM support is much better today so we will have to take another look at this for sure.

[orschiro]

When using LVM, if your / partition is on the LVM, it used to be
necessary to have a separate /bootpartition. In such a
configuration, the /boot partition is not be a partition of the LVM,
but rather a partition on the disk before the LVM starts. This is
because boot loaders could not read files from an LVM. So you could
never boot into your system on the LVM if it didn’t have a separate
/boot partition (see this
<https://help.ubuntu.com/11.10/serverguide/C/advanced-installation.html>
and this
<http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-lvm-diskdruid-manual.html>
for details).

The ability to read files from an LVM was added with GRUB2
<http://www.gnu.org/software/grub/manual/grub.html#Changes-from-GRUB-Legacy>,
which means that all recent versions of Ubuntu (Ubuntu 9.10 Karmic
Koala and later) have it <https://help.ubuntu.com/community/Grub2>.
So with proper configuration you can have your entire Ubuntu system
in an LVM without a separate /boot partition. See this page
<https://wiki.archlinux.org/index.php/GRUB2#LVM> for details about
how to configure this. (In fact, the only currently supported
<https://wiki.ubuntu.com/Releases> Ubuntu release that uses the
original GRUB instead of GRUB2 is Ubuntu 8.04 LTS Server; every
other non-EoL release—10.04 LTS, 10.10, 11.04, and 11.10—uses GRUB2.)

If you’re using LVM but not for your Ubuntu system drive, just for a
storage drive, or for some part of your system (perhaps for /home)
but not /, then a separate /boot partition is not necessary, even if
you are using an old (pre-GRUB2) system.

In summary, a separate /boot partition is largely a matter of
personal preference for systems that do not use LVM, whereas an
older system installed on an LVM might need one.

Source: http://askubuntu.com/questions/76095/what-is-the-use-of-boot-lvm-based-in-partitioning

On 01/20/2015 10:47 PM, Dustin Falgout wrote:

We enforce a boot partition when using LVM because grub required it (at that time). I believe grub's LVM support is much better today so we will have to take another look at this for sure.

— Reply to this email directly or view it on GitHub https://github.com/Antergos/Cnchi/issues/254#issuecomment-70740714.

​

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[karasu]

@lots0logs : So, what do we do? As we are using always the (nearly) latest Grub version, it should be ok to let users with lvm not have a boot partition, shouldn't it?

[lots0logs]

Yes but I'm not sure if any adjustments will need to be made to the grub install methods. I would consider this an enhancement to be implemented in a future version.