lvm¶

Linux Logical Volume Manager.

General flow¶

Physical volumes (pv) are grouped into volume groups (vg). Volume groups are sliced up into logical volumes (lv). Because of that, the general flow is something like:

## Partitioning is not necessary, so no need for fdisk or sgdisk
pvcreate /dev/sd{x..z}
vgcreate vg_scratch /dev/sd{x..z}
lvcreate -l 95%FREE -n lv_scratch vg_scratch
mkfs.ext4 /dev/vg_scratch/lv_scratch

Examples¶

Show a bunch of info¶

pvdisplay -v
pvs -v
pvs -a
pvs --segments
vgdisplay -v
vgs -v
vgs -a -o +devices

Show system disks and if they are in an LVM¶

lvmdiskscan

Show all logical volumes¶

lvs

Activate all volume groups¶

vgchange -a y

Create a physical volume¶

physical volumes are groups of physical disks that can be used to create logical volumes

pvcreate pv_name /dev/sdb2 /dev/sdc2

Create a logical volume¶

This creates a specifically named logical volume on a volume group named vg_data

lvcreate -L 10G -n lv_name vg_data

Show how each logical volume is set up¶

lvdisplay

Show free extents¶

vgs -o vg_free_count

Extend a volume group to 1TB¶

lvextend -L 1T /dev/vgroot/lv_srv && \
resize2fs /dev/mapper/vgroot-lv_srv && \
df -h /srv

Extend a volume group to its max¶

lvextend -l +100%FREE /dev/vgroot/lv_srv && \
resize2fs /dev/mapper/vgroot-lv_srv && \
df -h /srv