Arch Linux Infrastructure - Hypervisor - Resize VM

Shutdown the Guest VM.

Check the current size and view the partition name you want to expand using libvirt utility.

sudo virt-filesystems --long --parts --blkdevs -h -a indisk.qcow2

Name       Type       MBR  Size  Parent
/dev/sda1  partition  -    200M  /dev/sda
/dev/sda2  partition  -    1.0G  /dev/sda
/dev/sda3  partition  -    8.8G  /dev/sda
/dev/sda   device     -    10G   -

Create the new (20G) output disk.

QCOW2

sudo qemu-img create -f qcow2 -o preallocation=metadata outdisk.qcow2 20G

Formatting 'outdisk.qcow2', fmt=qcow2 size=21474836480 encryption=off cluster_size=65536 preallocation=metadata lazy_refcounts=off refcount_bits=16

Copy the old to the new while expand the appropriate partition (Assuming /dev/sda3).

sudo virt-resize --expand /dev/sda3 indisk.qcow2 outdisk.qcow2

[   0.0] Examining indisk.qcow2
**********

Summary of changes:

/dev/sda1: This partition will be left alone.

/dev/sda2: This partition will be left alone.

/dev/sda3: This partition will be resized from 8.8G to 18.8G.  The LVM PV 
on /dev/sda3 will be expanded using the 'pvresize' method.

**********
[   4.8] Setting up initial partition table on outdisk.qcow2
[  13.0] Copying /dev/sda1
[  13.7] Copying /dev/sda2
 100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[  21.3] Copying /dev/sda3
 100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
 100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ --:--
[ 444.0] Expanding /dev/sda3 using the 'pvresize' method

Resize operation completed with no errors.  Before deleting the old disk, 
carefully check that the resized disk boots and works correctly.

Rename the indisk.qcow2 file as a backup, rename the outdisk.qcow2 as indisk.qcow2 (or modify the guest XML).

mv indisk.qcow2 indiskBak20170820.qcow2
mv outdisk.qcow2 indisk.qcow2

Reboot the guest and test the new disk file carefully before deleting the original file.

Resize the partition inside the VM.

Red Hat Enterprise Linux & derivatives, CentOS, Scientific Linux, etc

vgdisplay

  --- Volume group ---
  VG Name               scientific_server
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  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               18.80 GiB
  PE Size               4.00 MiB
  Total PE              4813
  Alloc PE / Size       2253 / 8.80 GiB
  Free  PE / Size       2560 / 10.00 GiB
  VG UUID               5b1ccM-N1G7-zQum-QRXv-O8Us-dzJH-6LdAyC

lvdisplay

  --- Logical volume ---
  LV Path                /dev/scientific_server/swap
  LV Name                swap
  VG Name                scientific_server
  LV UUID                arRXqi-blzx-bjWb-IFbV-L7k1-L7SE-1GGsV7
  LV Write Access        read/write
  LV Creation host, time server.local, 2017-08-16 19:07:54 -0400
  LV Status              available
  # open                 2
  LV Size                1.00 GiB
  Current LE             256
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/scientific_server/root
  LV Name                root
  VG Name                scientific_server
  LV UUID                4rwPsh-0Xht-DXff-g5Vu-C3in-jMaV-5A7DqP
  LV Write Access        read/write
  LV Creation host, time server.local, 2017-08-16 19:07:55 -0400
  LV Status              available
  # open                 1
  LV Size                7.80 GiB
  Current LE             1997
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

lvextend --extents +100%FREE /dev/scientific_server/root

  Size of logical volume scientific_server/root changed from 7.80 GiB (1997 extents) to 17.80 GiB (4557 extents).
  Logical volume scientific_server/root successfully resized.

vgs

  VG                  #PV #LV #SN Attr   VSize  VFree
  scientific_server   1   2   0 wz--n- 18.80g    0 

xfs_growfs /dev/mapper/scientific_server-root

meta-data=/dev/mapper/scientific_server-root isize=512    agcount=4, agsize=511232 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=2044928, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               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 2044928 to 4666368

df -h

Filesystem                            Size  Used Avail Use% Mounted on
/dev/mapper/scientific_server-root   18G  7.8G   11G  44% /
devtmpfs                              486M     0  486M   0% /dev
tmpfs                                 496M     0  496M   0% /dev/shm
tmpfs                                 496M  6.7M  490M   2% /run
tmpfs                                 496M     0  496M   0% /sys/fs/cgroup
/dev/vda2                            1014M  176M  839M  18% /boot
/dev/vda1                             200M  9.5M  191M   5% /boot/efi
tmpfs                                 100M     0  100M   0% /run/user/0

Other File Systems

EXT3/4 Based File Systems

resize2fs /dev/centos/var

Written on August 20, 2017