Customize alternate install CD with UEFI?

Liam Proven lproven at gmail.com
Fri Jul 22 11:12:54 UTC 2016


On 22 July 2016 at 08:13, Josef Wolf <jw at raven.inka.de> wrote:
> Yesterday, I gave the installer on the live-DVD a try, and was somewhat
> disappointed:
>
> My plan was:
> 1. Shrink C:
> 2. Delete D:
> 3. Move the rescue disks, to get a big concatenated chunk of free room
> 4. separate /boot (300m)
> 5. encrypted LVM to hold /, swap and /data

Re point 5: I do not recommend mixing LVM with other partitioning schemes.

I don't like it and don't use it myself -- I think the Linux
implementation is not mature enough -- but I have experimented with
it. When I have used LVM on other OSes, e.g. Windows Server, it is all
or nothing: whole disk only.

This seems a good plan to me.

You want to keep Windows, in GPT partitions, _and_ have LVM. Bad plan, IMHO.

> I'm doing this scheme for many years with no problems.

On GUID disks?

> - Resizing worked, but to move the rescue partitions, I had to reboot into the
>   live-system and use gparted.

What's the problem with that?

> - Creating a big "physical volume for encrypted data" worked fine. But it can
>   hold only one partition?

Yes. That is correct, normal, desired behaviour. This is, as you have
said, a GPT disk. (Logical) partitions inside (an extended) partition
is a feature of the MBR partitioning scheme, the DOS system. GPT
replaces this completely. On GPT you cannot have partitions inside
partitions.

I have never tried putting Linux LVM inside an extended partition.
That sounds crazy to me but it might work, I guess. I think it will
not work on GPT.

> So I decided to delete it and create three
>   "physical volumes for encrypted data", one for /, one for swap and one for
>   /data.

Personally, I advocate /, /home and swap. Modern bootloaders can load
a kernel from any point on the disk so there is no need for a separate
/boot partition any more. It makes a system more fragile, as modern
kernels are very big -- circa a quarter of a gigabyte -- so it is very
easy to fill /boot and make a system impossible to update.

If you want to run with disk encryption -- something else I dislike
and will not use -- then a separate unencrypted /boot might help.
However, today, you need at least a gigabyte, I'd say. That's room for
4 kernels and a little bit spare. Ubuntu will happily retain 5+
kernels unless you regularly do

sudo apt-get autoremove -y

... so space for 4 is a minimum IMHO.

> BUT: now way: once created, there's no way to delete this big crypted
>   volume that I created before. Boot into the live system again to delete it.

This is one reason I dislike disk encryption. It makes re-partitioning
a massive pain. Been there, done that.

> - Third attempt:
>   1. create crypted volume for root, partitioner shows me three additional
>      entries: one at the original place, one at the very top, and one appended
>      with "crypt". I create / within the entry appended with "crypt"
>   2. create crypted volume for swap, same procedure as in (1.)
>   3. create crypted volume for data: The two additional entries won't
>      appear. How that?

I suspect that, with such a complicated scheme, you need to reboot
after removing any partition, so the system registers that it has
really gone.

>   4. Now I'm getting a warning that a non-crypted swap was found. I
>      double-checked three times: swap is within the crypted volume an no other
>      swap exists.

If your system is reasonably specified, why have swap at all? Why not
just use ZRAM or the ``swapspace'' command?

> At that point I stopped using the live-installer and went back to the
> alternate/server-CD, which worked fine.

The reboot might be key here.



-- 
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