systemd-gpt-auto-generator

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## Name

systemd-gpt-auto-generator — Generator for automatically discovering and mounting root, `/home` and `/srv` partitions, as well as discovering and enabling swap partitions, based on GPT partition type GUIDs.

## Synopsis

`/usr/lib/systemd/system-generators/systemd-gpt-auto-generator`

## Description

`systemd-gpt-auto-generator` is a unit generator that automatically discovers root, `/home`, `/srv` and swap partitions and creates mount and swap units for them, based on the partition type GUIDs of GUID partition tables (GPT). It implements the Discoverable Partitions Specification. Note that this generator has no effect on non-GPT systems, on systems where the units are explicitly configured (for example, listed in fstab(5)), or where the mount points are non-empty.

This generator will only look for root partitions on the same physical disk the EFI System Partition (ESP) is located on. It will only look for the other partitions on the same physical disk the root file system is located on. These partitions will not be searched on systems where the root file system is distributed on multiple disks, for example via btrfs RAID.

`systemd-gpt-auto-generator` is useful for centralizing file system configuration in the partition table and making manual configuration in `/etc/fstab` or suchlike unnecessary.

This generator looks for the partitions based on their partition type GUID. The following partition type GUIDs are identified:

Table 1. Partition Type GUIDs

Partition Type GUID | Name | Explanation
--- | --- | ---
44479540-f297-41b2-9af7-d131d5f0458a | `Root Partition (x86)` | On 32-bit x86 systems, the first x86 root partition on the disk the EFI ESP is located on is mounted to the root directory `/`.
4f68bce3-e8cd-4db1-96e7-fbcaf984b709 | `Root Partition (x86-64)` | On 64-bit x86 systems, the first x86-64 root partition on the disk the EFI ESP is located on is mounted to the root directory `/`.
69dad710-2ce4-4e3c-b16c-21a1d49abed3 | `Root Partition (32-bit ARM)` | On 32-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory `/`.
b921b045-1df0-41c3-af44-4c6f280d3fae | `Root Partition (64-bit ARM)` | On 64-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory `/`.
933ac7e1-2eb4-4f13-b844-0e14e2aef915 | Home Partition | The first home partition on the disk the root partition is located on is mounted to `/home`.
3b8f8425-20e0-4f3b-907f-1a25a76f98e8 | Server Data Partition | The first server data partition on the disk the root partition is located on is mounted to `/srv`.
0657fd6d-a4ab-43c4-84e5-0933c84b4f4f | Swap | All swap partitions located on the disk the root partition is located on are enabled.

The `/home` and `/srv` partitions may be encrypted in LUKS format. In this case a device mapper device is set up under the names `/dev/mapper/home` and `/dev/mapper/srv`. Note that this might create conflicts if the same partition is listed in `/etc/crypttab` with a different device mapper device name.

Also note that systemd-efi-boot-generator(8) will mount the EFI System Partition (ESP) to `/boot` if not otherwise mounted.

When using this generator in conjunction with btrfs file systems, make sure to set the correct default subvolumes on them, using btrfs subvolume set-default.

`systemd-gpt-auto-generator` implements the Generator Specification.

## See Also

systemd(1), systemd.mount(5), systemd.swap(5), systemd-fstab-generator(8), systemd-efi-boot-generator(8), systemd-cryptsetup@.service(8), cryptsetup(8), fstab(5), btrfs(8)