How to Increase the Size of a Linux LVM by Adding a New Disk⚓
Summary⚓
This article will explain in detail how to add a new virtual disk to an existing VM and add the storage to the existing logical volume so it can be utilized as one large disk.
Adding a New Virtual Disk⚓
Open XCP-ng Center and do the following:
- Select the VM the virtual disk will be added to.
- Click on the Storage tab and click Add...
- Give the new disk a name and select the amount of storage in GB, then click Add.
- Take note of the device path for the new disk
- ex.
/dev/xvdb - The disk should be detected automatically from within the VM, but in case it doesn't, reboot the VM.
Partition the New Disk⚓
We now need to partition the new /dev/xvdb disk so that it can be used. This is done by using fdisk -l, which will confirm the correct path for the disk and output the following:
─[[email protected]]─[~]
└──╼ #fdisk -l
Disk /dev/xvda: 2 TiB, 2147483648000 bytes, 4194304000 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
Disklabel type: dos
Disk identifier: 0x5ad16edb
Device Boot Start End Sectors Size Id Type
/dev/xvda1 2048 1499135 1497088 731M 83 Linux
/dev/xvda2 1501182 4194303999 4192802818 2T 5 Extended
/dev/xvda5 1501184 4194303999 4192802816 2T 8e Linux LVM
Disk /dev/mapper/ubuntu--vg-root: 2 TiB, 2145688485888 bytes, 4190797824 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
Disk /dev/mapper/ubuntu--vg-swap_1: 976 MiB, 1023410176 bytes, 1998848 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
Disk /dev/xvdb: 1.5 TiB, 1610612736000 bytes, 3145728000 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
Disklabel type: gpt
Disk identifier: 127CFA13-9DC6-4366-93C6-B36B5134C371
Now run fdisk again, but add the path to the disk.
- Use 'n' to add a new partition and select 1 for the Partition number.
- Use the defaults for First and Last sector.
- Use ‘t’ to change to a partitions system ID. In this case, this can be set to ’1′ automatically as this is currently the only partition.
- For the Hex Code, since this disk will be added to the existing logical volume, the Id can be noted from the Linux LVM listed above:
Device Boot Start End Sectors Size Id Type
/dev/xvda1 2048 1499135 1497088 731M 83 Linux
/dev/xvda2 1501182 4194303999 4192802818 2T 5 Extended
/dev/xvda5 1501184 4194303999 4192802816 2T 8e Linux LVM
- In this case, use the Hex Code for
/dev/xvda5. - Use 'w' for writing the table to the disk. This will also close
fdisk.
All the above steps should read like the following:
─[[email protected]]─[~]
└──╼ #fdisk /dev/xvdb
Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
Partition number (1-128, default 1): 1
First sector (34-3145727966, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-3145727966, default 3145727966):
Created a new partition 1 of type 'Linux filesystem' and of size 1.5 TiB.
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): 8e
Type of partition 1 is unchanged: Linux filesystem.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
Increasing the Logical Volume⚓
A physical volume will also need to be created to be added to the logical volume. This can be done with the pvcreate command.
┌─[[email protected]]─[~]
└──╼ #pvcreate /dev/xvdb1
Physical volume "/dev/xvdb1" successfully created
Now confirm the name of the current volume group using the vgdisplay command. The real focus will be on the VG Name line for the rest of this article.
[[email protected]]─[~]
└──╼ #vgdisplay
--- Volume group ---
VG Name ubuntu-vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 8
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 1.95 TiB
PE Size 4.00 MiB
Total PE 511816
Alloc PE / Size 511816 / 1.95 TiB
Free PE / Size 0 / 0
VG UUID EbOeff-YgpZ-f1w5-8HUh-ZScb-8pIH-i0ftwn
The vgextend command can now be used to extend the volume group by adding the physical volume of /dev/xvdb1.
[[email protected]]─[~]
└──╼ #vgextend ubuntu-vg /dev/xvdb1
Volume group "ubuntu-vg" successfully extended
Use the pvscan command to scan all the disks for physical volumes. The result of the scan should list the original volume of /dev/xvda5 and the newer volume of /dev/xvdb1.
─[[email protected]]─[~]
└──╼ #pvscan
PV /dev/xvda5 VG ubuntu-vg lvm2 [1.95 TiB / 0 free]
PV /dev/xvdb1 VG ubuntu-vg lvm2 [1.46 TiB / 1.46 TiB free]
Total: 2 [3.42 TiB] / in use: 2 [3.42 TiB] / in no VG: 0 [0 ]
Finally, confirm the name of the logical volume using the lvdisplay command.
[[email protected]]─[~]
└──╼ #lvdisplay
--- Logical volume ---
LV Path /dev/ubuntu-vg/root
LV Name root
VG Name ubuntu-vg
LV UUID VrCKdY-vEA8-WFRd-gisu-XD9Z-LFDQ-XGFdfq
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-12 00:18:59 -0400
LV Status available
# open 1
LV Size 1.95 TiB
Current LE 511572
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
The logical volume will now need to be extended using the lvextend command. This will extend the original volume of /dev/xvda5 over the newer volume of /dev/xvdb1.
─[[email protected]]─[~]
└──╼ #lvextend /dev/ubuntu-vg/root /dev/xvdb1
Size of logical volume ubuntu-vg/root changed from 1.95 TiB (511572 extents) to 3.42 TiB (895571 extents).
Logical volume root successfully resized.
Run the lvdisplay command again, which should now display the increased volume size from both volumes, now one volume.
[[email protected]]─[~]
└──╼ #lvdisplay
--- Logical volume ---
LV Path /dev/ubuntu-vg/root
LV Name root
VG Name ubuntu-vg
LV UUID VrCKdY-vEA8-WFRd-gisu-XD9Z-LFDQ-XGFdfq
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-12 00:18:59 -0400
LV Status available
# open 1
LV Size 3.42 TiB
Current LE 895571
Segments 3
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
Although the volume is now listing the correct volume size, that size is not yet usable until the resize2fs command is run. This will allow the system to make use of this new space.
─[[email protected]]─[~]
└──╼ #resize2fs /dev/ubuntu-vg/root
resize2fs 1.42.13 (17-May-2015)
Filesystem at /dev/ubuntu-vg/root is mounted on /; on-line resizing required
old_desc_blocks = 125, new_desc_blocks = 219
The filesystem on /dev/ubuntu-vg/root is now 917064704 (4k) blocks long.
The LVM has now been properly resized and is now usable by the VM. This can be confirmed with the df -h command, making note of the volume group - /dev/mapper/ubuntu--vg-root.
[[email protected]]─[~]
└──╼ #df -h
Filesystem Size Used Avail Use% Mounted on
udev 7.8G 0 7.8G 0% /dev
tmpfs 1.6G 9.2M 1.6G 1% /run
/dev/mapper/ubuntu--vg-root 3.4T 1.4T 1.9T 41% /
tmpfs 7.9G 120K 7.9G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 7.9G 0 7.9G 0% /sys/fs/cgroup
/dev/xvda1 720M 141M 543M 21% /boot
192.168.1.6:/volume1/Plex 15T 6.3T 8.1T 44% /mnt/Plex
tmpfs 1.6G 56K 1.6G 1% /run/user/1000
References⚓
https://www.rootusers.com/how-to-increase-the-size-of-a-linux-lvm-by-adding-a-new-disk/