[arch-general] Installation: How to get HDD > LUKS > GPT working in a clean way

[Paul Gideon Dann]

On 2 December 2016 at 22:29, Merlin Büge <toni at bluenox07.de> wrote:

>> Personally, I'd rather modify the start-up process a tiny bit so that
>> GPT inside LUKS gets parsed. I just try to strip off unnecessary
>> 'overhead' / layers of my system.

> If you have 8 GiB or more and not hibernating, don't bother with swap,
> it'd be a waste of disk space. In that case you could just put a btrfs
> volume straight on the LUKS container without the GPT. Problem solved as
> you don't need any more volume management than opening LUKS containers.


If another opinion helps, I've done some funky disk layouts at various
times, and I also think that if you need partitioning above the LUKS layer,
you'd do better to use LVM than GPT. GPT is intended to be used at the
lowest level of the stack, whereas LVM is well-supported at pretty much any
level. If you do go ahead with it, double-check that you won't get block
alignment issues in that stack that could affect IO performance.

However, if you say that you don't need the flexibility of LVM, I'd
certainly first try btrfs directly on top of LUKS.

Final consideration: if you want GRUB to open a LUKS container and then
load stage 2 from btrfs, you'll need a decent amount of storage for the
GRUB 1st stage, which on a traditional setup goes in free space you need
to account for after the MBR (or on the EFI partition for UEFI setups). In
your case, as the whole disk is LUKS and you have no partition table, have
you considered where the GRUB 1st stage will be stored? I use a USB stick
to boot GRUB stage 1 on my encrypted machines, and that may work for you
too.

Paul