0004 Disko with GPT partlabels

accepted date 2026 (backfilled 2026-07-08) deciders jawn #adr

  • Context

    • Host disk layouts were hand-partitioned and inconsistent; reinstalls were artisanal. Declarative partitioning needed a stable way for the bootloader and fstab to find partitions across device-name changes (/dev/sda vs /dev/nvme0n1).

  • Decision

    • Use disko for declarative partitioning on the x86 hosts, with mounts keyed on GPT partlabels (disk-main-*). Each host declares only its target device (homelab.disko.device in flake.nix).

  • Consequences

    • Installs and reinstalls are reproducible from the flake; device naming no longer matters.

    • Hosts labeled before the disko change fail to boot on a new generation unless relabeled to disk-main-*; relabel scripts live in nix/scripts/.

    • Rollback on an unmigrated host is the bootloader's previous-generation menu.

  • Links

Linked references 2

ADR

ADR/0004 Disko with GPT partlabels — declarative partitioning keyed on disk-main-* labels

Architecture/NixOS

Partitioning is declarative via disko with GPT partlabels (disk-main-*). Hosts installed before the migration need their partitions relabeled or they fail to boot — see ADR/0004 Disko with GPT partlabels and the scripts in nix/scripts/.

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