SYSTEMD-GPT-AUTO-GENERATORsystemd-gpt-auto-generaSYSTEMD-GPT-AUTO-GENERATOR(8)NAMEsystemd-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
/lib/systemd/system-generators/systemd-gpt-auto-generator
DESCRIPTIONsystemd-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[1]. Note that this generator has no effect on non-GPT
systems, or where the directories under the mount points are already
non-empty. Also, on systems where the units are explicitly configured
(for example, listed in fstab(5)), the units this generator creates are
overridden, but additional implicit dependencies might be created.
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 │ On 32-bit x86 │
│ │ (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 │ On 64-bit x86 │
│ │ (x86-64) │ 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 │ On 32-bit ARM │
│ │ (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 │ On 64-bit ARM │
│ │ (64-bit ARM) │ systems, the first │
│ │ │ ARM root partition │
│ │ │ on the disk the EFI │
│ │ │ ESP is located on │
│ │ │ is mounted to the │
│ │ │ root directory /. │
├─────────────────────────────────────┼─────────────────┼─────────────────────┤
│993d8d3d-f80e-4225-855a-9daf8ed7ea97 │ Root Partition │ On Itanium systems, │
│ │ (Itanium/IA-64) │ the first Itanium │
│ │ │ 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 │ The first server │
│ │ Partition │ 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. │
├─────────────────────────────────────┼─────────────────┼─────────────────────┤
│c12a7328-f81f-11d2-ba4b-00a0c93ec93b │ EFI System │ The first ESP │
│ │ Partition (ESP) │ located on the disk │
│ │ │ the root partition │
│ │ │ is located on is │
│ │ │ mounted to /boot or │
│ │ │ /efi, see below. │
└─────────────────────────────────────┴─────────────────┴─────────────────────┘
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.
Mount and automount units for the EFI System Partition (ESP) are
generated on EFI systems. The ESP is mounted to /boot, unless a mount
point directory /efi exists, in which case it is mounted there. Since
this generator creates an automount unit, the mount will only be
activated on-demand, when accessed. On systems where /boot (or /efi if
it exists) is an explicitly configured mount (for example, listed in
fstab(5)) or where the /boot (or /efi) mount point is non-empty, no
mount units are generated.
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 systemd.generator(7).
SEE ALSOsystemd(1), systemd.mount(5), systemd.swap(5), systemd-fstab-
generator(8), systemd-cryptsetup@.service(8), cryptsetup(8), fstab(5),
btrfs(8)NOTES
1. Discoverable Partitions Specification
https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/
systemd 236SYSTEMD-GPT-AUTO-GENERATOR(8)
