Default partitioning didn't use all space

[technobirb]

What's the reason that the default partitioning didn't use all available space? (The disk sector size is 4096.)
What's the right way to expand the LUKS partition to take up the free space?

[technobirb]

This is from a saved config (both with or without LUKS have the problem):

"partitions": [
                    {
                        "flags": [
                            "boot",
                            "esp"
                        ],
                        "fs_type": "fat32",
                        "size": {
                            "sector_size": {
                                "unit": "B",
                                "value": 4096
                            },
                            "unit": "GiB",
                            "value": 1
                        },
                        "start": {
                            "sector_size": {
                                "unit": "B",
                                "value": 4096
                            },
                            "unit": "MiB",
                            "value": 1
                        },
                        "status": "create",
                        "type": "primary"
                    },
                    {
                        "btrfs": [
                             ...
                        ],
                        "fs_type": "btrfs",
                        "size": {
                            "sector_size": {
                                "unit": "B",
                                "value": 4096
                            },
                            "unit": "B",
                            "value": 511033999360
                        },
                        "start": {
                            "sector_size": {
                                "unit": "B",
                                "value": 4096
                            },
                            "unit": "B",
                            "value": 1074790400
                        },
                        "status": "create",
                        "type": "primary"
                    }
                ],

1MiB + 1 GiB + 511033999360 B = 488385 MiB

> lsblk -b
NAME        MAJ:MIN RM         SIZE RO TYPE  MOUNTPOINTS
nvme0n1     259:0    0 512110190592  0 disk

512110190592 B = 488386.3359375 MiB
So indeed about 1.4 MiB un-allocated space.

[technobirb]

This is intentional:

1. Alignment: All partitions should align to 1 MiB boundary. So size is calculated & rounded in MiB.
2. Reserved space: 1 MiB at the start and the end.

In addition to the primary GPT header and Partition Entry Array, stored at the beginning of the disk, there is a backup GPT header and Partition Entry Array, stored at the end of the disk.

https://en.wikipedia.org/wiki/GUID_Partition_Table#Features
https://superuser.com/questions/1483928/why-do-windows-and-linux-leave-1mib-unused-before-first-partition

[svartkanin]

Can you raise an issue rather