SYSTEMD-GPT-AUTO-GENERATOR(8)

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 the partition type GUIDs of GUID partition tables (GPT). It implements the Discoverable Partitions Specification[1]. 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 search 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 32bit 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 64bit x86 systems the first x86-64 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[2].

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)

NOTES

1.  Discoverable Partitions Specification
    http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/

2.  Generator Specification
    http://www.freedesktop.org/wiki/Software/systemd/Generators