I am running CentOS 7 on a HyperV virtual server. I recently increased the size of the hard disk from 32GB to 64GB and used GParted Live to extend the partition, which seems to have worked as shown here:
However, when checking Disk Usage Analyser it is reporting it as 28.4GB:
In the terminal, I run df -h and it shows the following:
I have tried xfs_growfs /dev/mapper/centos-root -d but this says data size unchanged, skipping.
I am pretty inexperienced with Linux and, whilst trying to find a solution to this problem, most screenshots of df -h show /dev/sda1 and /dev/sda2. What are the extras shown here (several tmpfs and devtmpfs) and how do I get the system to recognise the full disk space?
Answer
You have a filesystem inside a logical volume inside volume group which encompasses all of your physical volume inside your now-64GiB block device.
What you have done through GParted was extend the physical volume to fill the block device, and the volume group automatically fills the physical volume, but you did not extend the logical volume.
As a result, the filesystem cannot grow because the logical volume did not grow.
The fix is a few commands. This one extends the logical volume to fill up the rest of the space in the volume group:
lvextend -l 100%VG /dev/mapper/centos-root
This one extends the filesystem:
xfs_growfs /
Full Example
Create a 1GiB block device as /dev/loop0 and later expand it to 2GiB:
root@node54 [/tmp]# truncate -s 1G demo.img
root@node54 [/tmp]# losetup loop0 demo.img
root@node54 [/tmp]# lsblk /dev/loop0
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 1G 0 loop
Set up LVM on the block device /dev/loop0:
root@node54 [/tmp]# pvcreate /dev/loop0
Physical volume "/dev/loop0" successfully created
root@node54 [/tmp]# pvdisplay /dev/loop0
"/dev/loop0" is a new physical volume of "1.00 GiB"
--- NEW Physical volume ---
PV Name /dev/loop0
VG Name
PV Size 1.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 0GC3Hx-pwqk-CsRV-UY8W-U2s0-3YOw-1pUUus
Now, a volume group:
root@node54 [/tmp]# vgcreate PandyDemo /dev/loop0
Volume group "PandyDemo" successfully created
root@node54 [/tmp]# vgdisplay PandyDemo
--- Volume group ---
VG Name PandyDemo
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 1020.00 MiB
PE Size 4.00 MiB
Total PE 255
Alloc PE / Size 0 / 0
Free PE / Size 255 / 1020.00 MiB
VG UUID ybaz6R-iVnK-a0kZ-Zd39-DwS8-sln1-R9zmfz
Now, a logical volume:
root@node54 [/tmp]# lvcreate -l 255 -n centos-root PandyDemo
Logical volume "centos-root" created
root@node54 [/tmp]# lvdisplay /dev/PandyDemo/centos-root
--- Logical volume ---
LV Path /dev/PandyDemo/centos-root
LV Name centos-root
VG Name PandyDemo
LV UUID RrhorY-JrIH-12Yu-nkEW-MSVb-YCin-o1XKbU
LV Write Access read/write
LV Creation host, time node54.deltik.org, 2016-02-10 02:56:46 -0600
LV Status available
# open 0
LV Size 1020.00 MiB
Current LE 255
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 252:3
I skipped the XFS filesystem creation on /dev/PandyDemo/centos-root for brevity, but you can create an XFS filesystem there now if you want to.
Now, shut down the volume group and block device so that we can add more disk space:
root@node54 [/tmp]# vgchange -an PandyDemo
0 logical volume(s) in volume group "PandyDemo" now active
root@node54 [/tmp]# losetup -d /dev/loop0
root@node54 [/tmp]# truncate -s 2G demo.img
Set up the block device again:
root@node54 [/tmp]# losetup loop0 demo.img
root@node54 [/tmp]# lsblk /dev/loop0
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 2G 0 loop
root@node54 [/tmp]# pvdisplay /dev/loop0
--- Physical volume ---
PV Name /dev/loop0
VG Name PandyDemo
PV Size 1.00 GiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 255
Free PE 0
Allocated PE 255
PV UUID 0GC3Hx-pwqk-CsRV-UY8W-U2s0-3YOw-1pUUus
Extend the physical volume to the entire block device, which is now 2GiB large. Notice the volume group also became 2GiB large, but the logical volume remained the same size as when we created it:
root@node54 [/tmp]# pvresize /dev/loop0
Physical volume "/dev/loop0" changed
1 physical volume(s) resized / 0 physical volume(s) not resized
root@node54 [/tmp]# pvdisplay /dev/loop0
--- Physical volume ---
PV Name /dev/loop0
VG Name PandyDemo
PV Size 2.00 GiB / not usable 3.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 511
Free PE 256
Allocated PE 255
PV UUID 0GC3Hx-pwqk-CsRV-UY8W-U2s0-3YOw-1pUUus
root@node54 [/tmp]# vgdisplay PandyDemo
--- Volume group ---
VG Name PandyDemo
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 2.00 GiB
PE Size 4.00 MiB
Total PE 511
Alloc PE / Size 255 / 1020.00 MiB
Free PE / Size 256 / 1.00 GiB
VG UUID ybaz6R-iVnK-a0kZ-Zd39-DwS8-sln1-R9zmfz
root@node54 [/tmp]# lvdisplay /dev/PandyDemo/centos-root
--- Logical volume ---
LV Path /dev/PandyDemo/centos-root
LV Name centos-root
VG Name PandyDemo
LV UUID RrhorY-JrIH-12Yu-nkEW-MSVb-YCin-o1XKbU
LV Write Access read/write
LV Creation host, time node54.deltik.org, 2016-02-10 02:56:46 -0600
LV Status NOT available
LV Size 1020.00 MiB
Current LE 255
Segments 1
Allocation inherit
Read ahead sectors auto
Extend the logical volume to be 100% the size of the volume group:
root@node54 [/tmp]# lvextend -l 100%VG /dev/PandyDemo/centos-root
Size of logical volume PandyDemo/centos-root changed from 1020.00 MiB (255 extents) to 2.00 GiB (511 extents).
Logical volume centos-root successfully resized
root@node54 [/tmp]# lvdisplay /dev/PandyDemo/centos-root
--- Logical volume ---
LV Path /dev/PandyDemo/centos-root
LV Name centos-root
VG Name PandyDemo
LV UUID RrhorY-JrIH-12Yu-nkEW-MSVb-YCin-o1XKbU
LV Write Access read/write
LV Creation host, time node54.deltik.org, 2016-02-10 02:56:46 -0600
LV Status NOT available
LV Size 2.00 GiB
Current LE 511
Segments 1
Allocation inherit
Read ahead sectors auto
At this point, you can reactivate the LVM with vgchange -ay PandyDemo and lvchange -ay /dev/PandyDemo/centos-root, and then, if you had created an XFS filesystem, you can grow it online after mounting it.
Additional Resources
If you are not using LVM and are just using GPT or MSDOS partitions and XFS, I have another detailed writeup on resizing XFS filesystems.
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