LVM
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LVM(Logical volume management) creates an easy to use layer over multiple physical disks. We can combine multiple disks and create logical storage volumes.
LVM features are[1]
- No restriction on disk size
- Increased disk throughput
- Mirroring volumes for business critical data
- Volume snapshots
- Easy backups and restores using snapshots
- Easy data relocation
- Resizing storage pools (add or remove disks) without reformatting disks
LVM Terminologies
| Type | Description | Example |
|---|---|---|
| Physical Volumes (PV) | Actual disks (e.g. /dev/sda, /dev,sdb, /dev/vdb and so on) | display physical volumes
|
| Volume Groups (VG) | Physical volumes are combined into volume groups. (e.g. my_vg = /dev/sda + /dev/sdb.) | |
| Logical Volumes (LV) | A volume group is divided up into logical volumes
(e.g. my_vg divided into my_vg/data, my_vg/backups, my_vg/home, my_vg/mysqldb and so on) |
Create LVM with two or more disk
#assuming we have two device sdb and sdc
_pvs=( /dev/sdb /dev/sdc )
for _pv in "${_pvs[@]}"
do
echo "Create PV (Physical Volume) : $_pv"
pvcreate $_pv
done
# Create VG (Volume Group) using PVs
sudo vgcreate $_vgname /dev/sdb /dev/sdc
# Create LV (Logical Volume) using VG
sudo lvcreate -n $_lvname -l 100%free --wipesignatures y --yes --zero y $_vgname
# Format LVM Partition depending on the filesystem
#sudo mkfs.ext4 /dev/$_vgname/$_lvname
#sudo mkfs.xfs /dev/$_vgname/$_lvname
# mount LVS to mount point, example /mnt/storage
sudo mkdir -p /mnt/storage
sudo mount /dev/$_vgname/$_lvname /mnt/storage
# add LVM into fstab
echo '/dev/$_vgname/$_lvname /mnt/storage ext4 defaults 0 0' | sudo tee -a /etc/fstab
sudo mount -a
Remove LVM
#unmount before to remove
sudo umount /mnt/storage
#disable LVM
sudo lvchange -an /dev/$_vgname/$_lvname
#delete LVM
sudo lvremove -f /dev/$_vgname/$_lvname
#delete VGs
sudo vgremove -f $_vgname
# Delete physical volumes
_pvs=( /dev/sdb /dev/sdc )
for _pv in "${_pvs[@]}"
do
echo "Delete PV (Physical Volume) : $_pv"
sudo pvremove -f $_pv
done
Display LVM status
PV status
# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 rl lvm2 a-- <2.00t 0
/dev/sdb vg01 lvm2 a-- <20.00g 0
/dev/sdc vg01 lvm2 a-- <10.00g 0
# pvdisplay
--- Physical volume ---
PV Name /dev/sdb
VG Name vg01
PV Size 20.00 GiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 5119
Free PE 0
Allocated PE 5119
PV UUID jkuGmw-Dcvm-GTo3-DMUj-h9xu-bG2I-l70qO0
--- Physical volume ---
PV Name /dev/sdc
VG Name vg01
PV Size 10.00 GiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2559
Free PE 0
Allocated PE 2559
PV UUID zOtlUy-Gh4t-KIVd-DLaq-qS9X-7SN4-d634eV
--- Physical volume ---
PV Name /dev/sda3
VG Name rl
PV Size <2.00 TiB / not usable 0
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 524031
Free PE 0
Allocated PE 524031
PV UUID enc5P4-hS0a-Tdpx-SUVj-8BSf-hsnM-ClWfmH
VG status
# vgs
VG #PV #LV #SN Attr VSize VFree
rl 1 3 0 wz--n- <2.00t 0
vg01 2 1 0 wz--n- 29.99g 0
# vgdisplay
--- Volume group ---
VG Name vg01
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 29.99 GiB
PE Size 4.00 MiB
Total PE 7678
Alloc PE / Size 7678 / 29.99 GiB
Free PE / Size 0 / 0
VG UUID QeeTHC-n8LG-5jqB-Z5yo-0cdg-f8Y5-dRJyjp
--- Volume group ---
VG Name rl
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size <2.00 TiB
PE Size 4.00 MiB
Total PE 524031
Alloc PE / Size 524031 / <2.00 TiB
Free PE / Size 0 / 0
VG UUID fVQYRJ-kNSC-XAec-TxNi-BF0U-GbIA-LaImvg
LV status
# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
home rl -wi-ao---- <1.93t
root rl -wi-ao---- 70.00g
swap rl -wi-ao---- 2.71g
lv01 vg01 -wi-ao---- 29.99g
# lvdisplay
--- Logical volume ---
LV Path /dev/vg01/lv01
LV Name lv01
VG Name vg01
LV UUID D6mc3r-lbtH-9gqc-3HjF-01Fg-7zrh-hPJzpC
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2024-01-11 01:28:30 -0500
LV Status available
# open 1
LV Size 29.99 GiB
Current LE 7678
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3
--- Logical volume ---
LV Path /dev/rl/swap
LV Name swap
VG Name rl
LV UUID cnVSkz-QhIp-UpeE-9Cb2-2neR-d6tc-YnJ5jy
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2024-01-10 21:19:57 -0500
LV Status available
# open 2
LV Size 2.71 GiB
Current LE 695
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/rl/home
LV Name home
VG Name rl
LV UUID eRA0eB-7PLr-JHaR-P8l7-UMoP-V1mz-eVVEJJ
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2024-01-10 21:19:58 -0500
LV Status available
# open 1
LV Size <1.93 TiB
Current LE 505416
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/rl/root
LV Name root
VG Name rl
LV UUID yRgfqu-8slv-AzW8-LaUp-Mkto-fSJh-MOIAG4
LV Write Access read/write
LV Creation host, time localhost.localdomain, 2024-01-10 21:19:59 -0500
LV Status available
# open 1
LV Size 70.00 GiB
Current LE 17920
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0