This topic includes:
Commands:
lvextend adds space to a logical volume. The space needs to be available in the volume group.
When extending Logical Volumes, you do not need to unmount the partition (however you will need to extend the file system afterwards, or if the filesystems supports, use the '-r' flag to automatically resize the filesystem).
Checking for available space
Use vgs to see the available space of the volume group
# vgs vg1
VG #PV #LV #SN Attr VSize VFree
vg1 3 1 0 wz--n- <8.99g <4.99g
| |- Available VG space (not allocated to a LV)
|- Total size of VG
You can use lvs to confirm that the LV is using the difference of the previous values
# lvs vg1
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv1 vg1 -wi-a----- 4.00g
Or just use vgdisplay and check the PE sizes
# vgdisplay vg1 | grep 'PE /'
Alloc PE / Size 1024 / 4.00 GiB
Free PE / Size 1277 / <4.99 GiB
Extend volume to specified size (k/m/g)
# lvextend -L6G /dev/vg1/lv1
Size of logical volume vg1/lv1 changed from 5.39 GiB (1381 extents) to 6.00 GiB (1536 extents).
Logical volume vg1/lv1 successfully resized.
Extend the volume by 1GB
# lvextend -L+1G /dev/vg1/lv1
Size of logical volume vg1/lv1 changed from 6.00 GiB (1536 extents) to 7.00 GiB (1792 extents).
Logical volume vg1/lv1 successfully resized.
Extend for the full available space in the VG
# lvextend -l +100%FREE /dev/vg1/lv1
Size of logical volume vg1/lv1 changed from 7.00 GiB (1792 extents) to <8.99 GiB (2301 extents).
Logical volume vg1/lv1 successfully resized.
⚠️ WARNING: lvextend -l +100%FREE /dev/vg1/lv1 (without the plus size) will not work
Extend to the percentage of the VG (60% or 8.99 = 5.394)
# lvextend -l 60%VG /dev/vg1/lv1
Size of logical volume vg1/lv1 changed from 4.00 GiB (1024 extents) to 5.39 GiB (1381 extents).
Logical volume vg1/lv1 successfully resized.
You can also use the 'PE' size
# lvextend -l +1740 /dev/RHCSA/pinehead
Size of logical volume RHCSA/pinehead changed from <3.20 GiB (818 extents) to 9.99 GiB (2558 extents).
Logical volume RHCSA/pinehead successfully resized.
📝 NOTE: The 'r' option will attempt to resize the filesystem (if possible)
Be careful when reducing an LV's size, because data in the reduced area is lost. Ensure that any file system on the LV is resized before running lvreduce so that the removed extents are not in use by the file system.
You can use two commands to shrink a logical volume:
lvreduce reduces the size of an LV. The freed logical extents are returned to the VG to be used by other LVs.lvresize resizes an LV in the same way as lvextend and lvreduce.Shrink a logical volume by 2GB
# lvresize -L-2G /dev/vg1/lv1
WARNING: Reducing active logical volume to <6.99 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg1/lv1? [y/n]: y
Size of logical volume vg1/lv1 changed from <8.99 GiB (2301 extents) to <6.99 GiB (1789 extents).
Logical volume vg1/lv1 successfully resized.
Shrink a logical volume to 30% of the volume group size
# lvreduce -l 30%VG /dev/vg1/lv1
WARNING: Reducing active logical volume to <2.70 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg1/lv1? [y/n]: y
Size of logical volume vg1/lv1 changed from <6.99 GiB (1789 extents) to <2.70 GiB (691 extents).
Logical volume vg1/lv1 successfully resized.
Commands:
After extending the logical volume, if you did not use the -r option you will need to extend the filesystem manually.
Check the size of the logical volume with 'lvs' or 'fdisk'
# vgs vg2
VG #PV #LV #SN Attr VSize VFree
vg2 3 1 0 wz--n- <6.99g 0
# fdisk -l /dev/vg2/xfs
Disk /dev/vg2/xfs: 7 GiB, 7503609856 bytes, 14655488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Compare it to the filesystem size with 'df'
# df -hT /mnt/xfs
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg2-xfs xfs 6.0G 75M 6.0G 2% /mnt/xfs
Resize the filesystem with 'xfs_growfs' by giving the mount point
# xfs_growfs /mnt/xfs
meta-data=/dev/mapper/vg2-xfs isize=512 agcount=4, agsize=392704 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=1570816, 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=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 1570816 to 1831936
Confirm that it has changed
# df -hT /mnt/xfs
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg2-xfs xfs 7.0G 83M 6.9G 2% /mnt/xfs
Check the size of the logical volume with 'lvs' or 'fdisk'
# lvs vg1
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
ext4 vg1 -wi-ao---- <6.99g
# fdisk -l /dev/vg1/ext4
Disk /dev/vg1/ext4: 7 GiB, 7503609856 bytes, 14655488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Compare it to the filesystem size with 'df'
# df -hT /mnt/ext4/
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg1-ext4 ext4 5.9G 24M 5.5G 1% /mnt/ext4
Resize the filesystem with 'resize2fs' by giving the device name
# resize2fs /dev/mapper/vg1-ext4
resize2fs 1.45.6 (20-Mar-2020)
Filesystem at /dev/mapper/vg1-ext4 is mounted on /mnt/ext4; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mapper/vg1-ext4 is now 1831936 (4k) blocks long.
Confirm that it has changed
# df -hT /mnt/ext4
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg1-ext4 ext4 6.9G 27M 6.5G 1% /mnt/ext4