Setup LVM on a VM
How to setup Logical Volume Manager on a VM.
Install LVM.
<pre lang="bash">
yum install lvm2
Check the disks available. We are going to run LVM on /dev/sdb.
<pre lang="bash">
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 200M 0 part /boot/efi
└─sda2 8:2 0 19.8G 0 part /
sdb 8:16 0 20G 0 disk
Create a physical volume on /dev/sdb.
<pre lang="bash">
$ pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created.
$ pvs
PV VG Fmt Attr PSize PFree
/dev/sdb vg lvm2 a--
<p>Create a volume group called vg.</p>
<pre lang="bash">
$ vgcreate vg /dev/sdb
Volume group "vg" successfully created
$ vgs
VG #PV #LV #SN Attr VSize VFree
vg 1 0 0 wz--n-
<p>Create a 10GB logical volume group called data.</p>
<pre lang="bash">
$ lvcreate -L 10G -n data vg
Logical volume "data" created.
$ lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
data vg -wi-a----- 10.00g
<p>Format the volume group and mount it.</p>
<pre lang="bash">
$ mkfs.xfs /dev/vg/data
meta-data=/dev/vg/data isize=512 agcount=4, agsize=655360 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=2621440, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
Discarding blocks...Done.
$ mount /dev/vg/data /mnt
<p>Check your logical volume. It says 10GB.</p>
<pre lang="bash">
$ df -Th
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 385M 0 385M 0% /dev
tmpfs tmpfs 403M 0 403M 0% /dev/shm
tmpfs tmpfs 403M 5.5M 398M 2% /run
tmpfs tmpfs 403M 0 403M 0% /sys/fs/cgroup
/dev/sda2 xfs 20G 2.9G 17G 15% /
/dev/sda1 vfat 200M 5.8M 195M 3% /boot/efi
tmpfs tmpfs 81M 0 81M 0% /run/user/1000
/dev/mapper/vg-data xfs 10G 104M 9.9G 2% /mnt
<p>Let's now extend the logical volume to 20GB.</p>
<pre lang="bash">
$ lvextend -l +100%FREE /dev/vg/data
Size of logical volume vg/data changed from 10.00 GiB (2560 extents) to
<p>Although lsblk says 20GB, our logical volume still says 10GB. </p>
<pre lang="bash">
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 200M 0 part /boot/efi
└─sda2 8:2 0 19.8G 0 part /
sdb 8:16 0 20G 0 disk
└─vg-data 253:0 0 20G 0 lvm /mnt
$ df -Th
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 385M 0 385M 0% /dev
tmpfs tmpfs 403M 0 403M 0% /dev/shm
tmpfs tmpfs 403M 5.5M 398M 2% /run
tmpfs tmpfs 403M 0 403M 0% /sys/fs/cgroup
/dev/sda2 xfs 20G 2.9G 17G 15% /
/dev/sda1 vfat 200M 5.8M 195M 3% /boot/efi
tmpfs tmpfs 81M 0 81M 0% /run/user/1000
/dev/mapper/vg-data xfs 10G 104M 9.9G 2% /mnt
<p>We need to grow the file system.</p>
<pre lang="bash">
$ xfs_growfs /dev/vg/data
meta-data=/dev/mapper/vg-data isize=512 agcount=4, agsize=655360 blks
= sectsz=4096 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=2621440, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=4096 sunit=1 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2621440 to 5241856
<p>Let's check again.</p>
<pre lang="bash">
$ df -Th
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 385M 0 385M 0% /dev
tmpfs tmpfs 403M 0 403M 0% /dev/shm
tmpfs tmpfs 403M 5.5M 398M 2% /run
tmpfs tmpfs 403M 0 403M 0% /sys/fs/cgroup
/dev/sda2 xfs 20G 2.9G 17G 15% /
/dev/sda1 vfat 200M 5.8M 195M 3% /boot/efi
tmpfs tmpfs 81M 0 81M 0% /run/user/1000
/dev/mapper/vg-data xfs 20G 176M 20G 1% /mnt
<p>It now says 20GB.</p>