Manual installation with GPT mode and properly aligned partitions?

[thorazine74]

I tried to install OPNsense on a virtual machine, using the manual installation mode the installer creates the old MBR partition layout with BSD slices, which are of course misaligned to current SSDs 4K sectors (and modern HDDs) and aligned to cylinders.

Ive tried to manually create the GPT partition layout beforehand (basically mimicking the guided install layout, only different sizes for root and swap partitions) but it seems the manual installer is not written to handle that, so I assume the manual installer is hardcoded to do MBR installation but the guided installation prompts if you want MBR or GPT, but not the manual installation?

Is there any workaround to this?

On a side note, shouldnt be more logical that the installer was designed to end up with a basically identical system partitions layout in both modes, only with different amount of prompts and customizations?

[franco]

Hi there,

GPT guided mode was written with 4k alignment in place, but the main goal was to get UEFI to work. The manual mode doesn't do GPT for historic reasons.

We have the guided mode to do "basically identical system partitions layouts", but each mode is different, especially with the extra layout required for UEFI trampoline partition. I guess they are the same otherwise as they both create one root partition and a probable swap partition with the same rules for sizing in place.

Long story short: why do you need a manual mode? What's different about your desired partitioning?


Cheers,
Franco

[thorazine74]

I would like to be able to limit the root partition's size (leaving free space on the SSD) and increase the swap partition's size, using a GPT disk layout with 4k-aligned partitions.

I'm not sure what are the historical reasons for keeping the old MBR layout with cylinder alignment but I'm not sure if that makes sense anymore, doesn't all disks since many years ago recommend 4K alignment?

IMO it doesnt make sense to have a choice to use either GPT+4K or MBR+CHS in guided mode but being forced to use MBR+CHS in manual mode...

[franco]

You are right. In an ideal world where the third law of thermodynamics does not hold any power over use mere open source developers it does not make sense. We, however, are bound by the work that is put into open source and the installer is one instance where few contribute to make the logical outcome what you see, not what you expect.

That being said, there are a couple of tickets regarding ZFS support and other things that need to be fixed first so I can't make any commitment on improving the manual installer at this time.  Though I am happy to help shape and review submissions to:

https://github.com/opnsense/bsdinstaller


Cheers,
Franco