You should create your LVM Volumes between the partitioning and formatting steps of the installation procedure. Instead of directly formatting a partition to be your root file system, the file system will be created inside a logical volume (LV).
- Install the required packages. (refer to LVM#Installation)
- Create partition(s) where your physical volumes (PVs) will reside.
- Create your PVs. If you have one disk it is best to just create one PV in one large partition. If you have multiple disks you can create partitions on each of them and create a PV on each partition.
- Create your volume group (VG) and add all PVs to it.
- Create logical volumes (LVs) inside that VG.
- Continue with Installation guide#Format the partitions.
- When you reach the “Create initial ramdisk environment” step in the Installation guide, add the
/etc/mkinitcpio.conf(see below for details).
/bootcannot reside in LVM when using a boot loader which does not support LVM; you must create a separate
/bootpartition and format it directly. While this partition is already necessary for UEFI/GPT it is an additional partition for both BIOS/MBR and BIOS/GPT. Create the partition
/bootfor BIOS systems irrespective of the partition table and create a
Linux filesystemon it (partition type
8300in gdisk). Mount the created partition to
/boot. Only GRUB is known to support LVM. Nevertheless, it requires this separate boot partition.
You will follow along with the installation guide until you come to Installation guide#Partition the disks. At this point you will diverge and doing all your partitioning with LVM in mind.
First, partition your disks as required before configuring LVM.
Create the partitions:
- If you use GUID Partition Table, set the partition type GUID to
Linux LVMin fdisk and
- If you use Master Boot Record partition table, set the partition type ID to
Linux LVMin fdisk).
Create physical volumes
To list all your devices capable of being used as a physical volume:
Create a physical volume on them:
# pvcreate DEVICE
This command creates a header on each device so it can be used for LVM. As defined in LVM#LVM building blocks, DEVICE can be any block device, e.g. a disk
/dev/sda, a partition
/dev/sda2 or a loop back device. For example:
# pvcreate /dev/sda2
You can track created physical volumes with:
You can also get summary information on physical volumes with:
Create and extend your volume group
First you need to create a volume group on any one of the physical volumes:
# vgcreate volume_group physical_volume
# vgcreate VolGroup00 /dev/sda2
Seefor a list of valid characters for volume group names.
Extending the volume group is just as easy:
# vgextend volume_group physical_volume
For example, to add both
sdc to your volume group:
# vgextend VolGroup00 /dev/sdb1 # vgextend VolGroup00 /dev/sdc
You can track how your volume group grows with:
This is also what you would do if you wanted to add a disk to a RAID or mirror group with failed disks.
Combined creation of physical volumes and volume groups
LVM allows you to combine the creation of a volume group and the physical volumes in one easy step. For example, to create the group VolGroup00 with the three devices mentioned above, you can run:
# vgcreate VolGroup00 /dev/sda2 /dev/sdb1 /dev/sdc
This command will first set up the three partitions as physical volumes (if necessary) and then create the volume group with the three volumes. The command will warn you if it detects an existing filesystem on any devices.
Create logical volumes
- If you wish to use snapshots, logical volume caching, thin provisioned logical volumes or RAID see LVM#Logical volumes.
- If a logical volume will be formatted with ext4, leave at least 256 MiB free space in the volume group to allow using . After creating the last volume with
-l 100%FREE, this can be accomplished by reducing its size with
lvreduce -L -256M volume_group/logical_volume.
Now we need to create logical volumes on this volume group. You create a logical volume with the next command by specifying the new volume's name and size, and the volume group it will reside on:
# lvcreate -L size volume_group -n logical_volume
# lvcreate -L 10G VolGroup00 -n lvolhome
This will create a logical volume that you can access later with
/dev/VolGroup00/lvolhome. Just like volume groups, you can use any name you want for your logical volume when creating it besides a few exceptions listed in .
You can also specify one or more physical volumes to restrict where LVM allocates the data. For example, you may wish to create a logical volume for the root filesystem on your small SSD, and your home volume on a slower mechanical drive. Simply add the physical volume devices to the command line, for example:
# lvcreate -L 10G VolGroup00 -n lvolhome /dev/sdc1
To use all the free space left in a volume group, use the next command:
# lvcreate -l 100%FREE volume_group -n logical_volume
You can track created logical volumes with:
modprobe dm_mod) for the above commands to succeed.
Format and mount logical volumes
Your logical volumes should now be located in
/dev/YourVolumeGroupName/. If you cannot find them, use the next commands to bring up the module for creating device nodes and to make volume groups available:
# modprobe dm_mod # vgscan # vgchange -ay
Now you can format your logical volumes and mount them as normal partitions (see mount a file system for additional details):
# mkfs.fstype /dev/volume_group/logical_volume # mount /dev/volume_group/logical_volume /mountpoint
# mkfs.ext4 /dev/VolGroup00/lvolhome # mount /dev/VolGroup00/lvolhome /home
/dev/Volgroup00/lvolhome). Do not select the actual partitions on which logical volumes were created (do not use:
Configure the system
Make sure the installed.package is
lvm2hook. If you are running mkinitcpio in an arch-chroot for a new installation, must be installed inside the arch-chroot for mkinitcpio to find the
lvm2hook. If only exists outside the arch-chroot, mkinitcpio will output
Error: Hook 'lvm2' cannot be found.
- If your root filesystem is on LVM RAID see #Configure mkinitcpio for RAID.
Adding mkinitcpio hooks
In case your root filesystem is on LVM, you will need to enable the appropriate mkinitcpio hooks, otherwise your system might not boot. Enable:
lvm2for the default busybox-based initramfs
lvm2for systemd-based initramfs
udev is there by default. Edit the file and insert
filesystems like so:
HOOKS=(base udev ... block lvm2 filesystems)
For systemd based initramfs:
HOOKS=(base systemd ... block lvm2 filesystems)
Afterwards, you can continue in normal installation instructions with the create an initial ramdisk step.
Configure mkinitcpio for RAID
If your root filesystem is on LVM RAID additionally to the
lvm2 hook, you need to add
dm-raid and the appropriate RAID modules (e.g.
raid456) to the MODULES array in
dm_integrity module is needed if you created RAID with integrity checksums (
--raidintegrity option in
For busybox based initramfs:
MODULES=(dm-raid dm_integrity raid0 raid1 raid10 raid456) HOOKS=(base udev ... block lvm2 filesystems)
For systemd based initramfs:
MODULES=(dm-raid dm_integrity raid0 raid1 raid10 raid456) HOOKS=(base systemd ... block lvm2 filesystems)
For systems using LVM thin volumes the location of systemd between udev and block causes the malfunction of the thin volume. just with the parameters (base udev autodetect modconf block lvm2 filesystems keyboard fsck) works: root FS inside a lvm logical volume, and other LVM's (normal and thin) at other locations.
Kernel boot options
If the root file system resides in a logical volume, the
root= kernel parameter must be pointed to the mapped device, e.g