Resizing the disk on a KVM system is rather straight-forward, but it sure does require that you get the steps right!
The Steps
- Remove snapshots
- Stop the VM
- Enlarge the disk itself
- In GUI, find your VM. Choose Hardware, then click on the disk and then Resize Disk
- From CLI, run one of the following:
qemu-img resize <disk> +<size>G- Example:
qemu-img resize /vm/images/158/vm-158-disk-1.qcow2 +32Gto increase image size by 32GB
- Example:
qm resize <vmid> <disk> +<size>G- Example:
qm resize 158 /vm/images/158/vm-158-disk-1.qcow2 +32Gto increase VM #158’s disk by 32GB
- Example:
- Start the VM and resize the partition then LVM
- Run fdisk inside your guest and remove the partition that you want to extend
[root@centos7 ~]# lsblk | grep disk sda 8:0 0 64G 0 disk [root@centos7 ~]# fdisk /dev/sda Welcome to fdisk (util-linux 2.23.2). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): p Disk /dev/sda: 68.7 GB, 68719476736 bytes, 134217728 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 label type: dos Disk identifier: 0x000be40f Device Boot Start End Blocks Id System /dev/sda1 * 2048 2099199 1048576 83 Linux /dev/sda2 2099200 67108863 32504832 8e Linux LVM Command (m for help): d Partition number (1,2, default 2): 2 Partition 2 is deleted Command (m for help): p Disk /dev/sda: 68.7 GB, 68719476736 bytes, 134217728 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 label type: dos Disk identifier: 0x000be40f Device Boot Start End Blocks Id System /dev/sda1 * 2048 2099199 1048576 83 Linux Command (m for help): n Partition type: p primary (1 primary, 0 extended, 3 free) e extended Select (default p): p Partition number (2-4, default 2): First sector (2099200-134217727, default 2099200): Using default value 2099200 Last sector, +sectors or +size{K,M,G} (2099200-134217727, default 134217727): Using default value 134217727 Partition 2 of type Linux and of size 63 GiB is set Command (m for help): p Disk /dev/sda: 68.7 GB, 68719476736 bytes, 134217728 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 label type: dos Disk identifier: 0x000be40f Device Boot Start End Blocks Id System /dev/sda1 * 2048 2099199 1048576 83 Linux /dev/sda2 2099200 134217727 66059264 83 Linux Command (m for help): t Partition number (1,2, default 2): 2 Hex code (type L to list all codes): 8e Changed type of partition 'Linux' to 'Linux LVM' Command (m for help): p Disk /dev/sda: 68.7 GB, 68719476736 bytes, 134217728 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 label type: dos Disk identifier: 0x000be40f Device Boot Start End Blocks Id System /dev/sda1 * 2048 2099199 1048576 83 Linux /dev/sda2 2099200 134217727 66059264 8e Linux LVM Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8) Syncing disks. [root@centos7 ~]# - Reboot the VM
- Resize the LVM physical volume
[root@centos7 ~]# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name cl_vm-07 PV Size <31.00 GiB / not usable 3.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 7935 Free PE 1 Allocated PE 7934 PV UUID 8dCBQY-gbR5-xy4k-U0Ap-fDfv-4idB-J3rD5V [root@centos7 ~]# pvresize /dev/sda2 Physical volume "/dev/sda2" changed 1 physical volume(s) resized / 0 physical volume(s) not resized [root@centos7 ~]# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name cl_vm-07 PV Size <63.00 GiB / not usable 2.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 16127 Free PE 8193 Allocated PE 7934 PV UUID 8dCBQY-gbR5-xy4k-U0Ap-fDfv-4idB-J3rD5V
- Resize the logical volume
[root@pete-dev-centos7 ~]# lvdisplay --- Logical volume --- LV Path /dev/cl_vm-07/swap LV Name swap VG Name cl_vm-07 LV UUID 6E7b0t-0q8s-Bm6m-LqRI-jwfY-GQcr-eMmERY LV Write Access read/write LV Creation host, time vm-07, 2017-05-23 08:22:40 -0400 LV Status available # open 2 LV Size 2.00 GiB Current LE 512 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/cl_vm-07/root LV Name root VG Name cl_vm-07 LV UUID aeVwKb-Th7A-al03-aKAq-HONA-mciK-Nsew02 LV Write Access read/write LV Creation host, time vm-07, 2017-05-23 08:22:40 -0400 LV Status available # open 1 LV Size 28.99 GiB Current LE 7422 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 [root@centos7 ~]# lvresize /dev/cl_vm-07/root -l +8193 Size of logical volume cl_vm-07/root changed from 28.99 GiB (7422 extents) to <61.00 GiB (15615 extents). Logical volume cl_vm-07/root successfully resized. ### NOTE: ### You can also use a one-liner: ### lvextend /dev/cl_vm-07/root /dev/sda2 ### Without any options, it will use the maximum size in that group [root@centos7 ~]# lvdisplay --- Logical volume --- LV Path /dev/cl_vm-07/swap LV Name swap VG Name cl_vm-07 LV UUID 6E7b0t-0q8s-Bm6m-LqRI-jwfY-GQcr-eMmERY LV Write Access read/write LV Creation host, time vm-07, 2017-05-23 08:22:40 -0400 LV Status available # open 2 LV Size 2.00 GiB Current LE 512 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/cl_vm-07/root LV Name root VG Name cl_vm-07 LV UUID aeVwKb-Th7A-al03-aKAq-HONA-mciK-Nsew02 LV Write Access read/write LV Creation host, time vm-07, 2017-05-23 08:22:40 -0400 LV Status available # open 1 LV Size <61.00 GiB Current LE 15615 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0
- Grow the filesystem
### NOTE: ### In Centos 7 default filesystem is xfs. ### Also noteworthy: xfs file system supports extend not reduce ### If you want to resize the filesystem use xfs_growfs rather than resize2fs. [root@centos7 ~]# xfs_growfs /dev/vm-07/root meta-data=/dev/mapper/vm--07-root isize=512 agcount=4, agsize=1900032 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0 data = bsize=4096 blocks=7600128, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal bsize=4096 blocks=3711, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 7600128 to 15989760 ### Note: For ext4 filesystem use [root@centos7 ~]#resize2fs /dev/vm-07/root [root@centos7 ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vm--07-root 61G 23G 39G 37% / devtmpfs 909M 0 909M 0% /dev tmpfs 920M 0 920M 0% /dev/shm tmpfs 920M 8.4M 912M 1% /run tmpfs 920M 0 920M 0% /sys/fs/cgroup /dev/sda1 1014M 279M 736M 28% /boot tmpfs 184M 0 184M 0% /run/user/1002 tmpfs 184M 0 184M 0% /run/user/1001
- Run fdisk inside your guest and remove the partition that you want to extend