virt-resizeによるディスクサイズ拡張の実行例
ゲストOSはCentOS 7で、LVM使用、ファイルシステムはXFS。 ディスクイメージはqcow2形式で、サイズを8Gから10Gに変更。
実行前のゲストの状態
[root@guest ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 988M 0 988M 0% /dev tmpfs 1000M 0 1000M 0% /dev/shm tmpfs 1000M 8.5M 992M 1% /run tmpfs 1000M 0 1000M 0% /sys/fs/cgroup /dev/mapper/centos-root 6.2G 1.3G 5.0G 20% / /dev/vda1 1014M 137M 878M 14% /boot tmpfs 200M 0 200M 0% /run/user/0 [root@guest ~]# vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 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 <7.00 GiB PE Size 4.00 MiB Total PE 1791 Alloc PE / Size 1791 / <7.00 GiB Free PE / Size 0 / 0 VG UUID Jq1KXV-oAJ4-QChG-3u3w-Rrwi-GvXH-0UaKhf [root@guest ~]# lvdisplay --- Logical volume --- LV Path /dev/centos/swap LV Name swap VG Name centos LV UUID n3c1Xq-YvEF-8uYb-x5lA-cssY-P8vG-JE3dwm LV Write Access read/write LV Creation host, time localhost, 2022-04-29 05:14:00 +0900 LV Status available # open 2 LV Size 820.00 MiB Current LE 205 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/centos/root LV Name root VG Name centos LV UUID g8yMUy-1eYI-BIN2-9khy-7cjA-n8fn-dOUcRa LV Write Access read/write LV Creation host, time localhost, 2022-04-29 05:14:00 +0900 LV Status available # open 1 LV Size <6.20 GiB Current LE 1586 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 [root@guest ~]# pvdisplay --- Physical volume --- PV Name /dev/vda2 VG Name centos PV Size <7.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 1791 Free PE 0 Allocated PE 1791 PV UUID U8CR49-1Dmk-gNed-Qb8W-UBem-aUIT-npeWV8
サイズを拡張するLVのLV Pathが必要。
サイズを拡張したディスクイメージを作成
仮想マシンを停止してディスクの状態表示。
[root@kvmhost ~]# virsh shutdown centos7 [root@kvmhost ~]# virsh dumpxml centos7 | xpath /domain/devices/disk/source Found 1 nodes: -- NODE -- <source file="/var/lib/libvirt/images/centos7.qcow2" /> [root@kvmhost ~]# virt-filesystems --long --parts --blkdevs -h -a /var/lib/libvirt/images/centos7.qcow2 Name Type MBR Size Parent /dev/sda1 partition 83 1.0G /dev/sda /dev/sda2 partition 8e 7.0G /dev/sda /dev/sda device - 8.0G -
新しいディスクイメージを作成して、サイズを拡張しながらディスクの中身をコピー。
[root@kvmhost ~]# qemu-img create -f qcow2 -o preallocation=metadata /var/lib/libvirt/images/centos7-new.qcow2 10G Formatting '/var/lib/libvirt/images/centos7-new.qcow2', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off [root@kvmhost ~]# virt-resize --expand /dev/sda2 --LV-expand /dev/centos/root /var/lib/libvirt/images/centos7.qcow2 /var/lib/libvirt/images/centos7-new.qcow2 [ 0.0] Examining /var/lib/libvirt/images/centos7.qcow2 ********** Summary of changes: /dev/sda1: This partition will be left alone. /dev/sda2: This partition will be resized from 7.0G to 9.0G. The LVM PV on /dev/sda2 will be expanded using the ‘pvresize’ method. /dev/centos/root: This logical volume will be expanded to maximum size. The filesystem xfs on /dev/centos/root will be expanded using the ‘xfs_growfs’ method. ********** [ 5.6] Setting up initial partition table on /var/lib/libvirt/images/centos7-new.qcow2 [ 6.2] Copying /dev/sda1 [ 9.4] Copying /dev/sda2 [ 33.5] Expanding /dev/sda2 using the ‘pvresize’ method [ 33.5] Expanding /dev/centos/root using the ‘xfs_growfs’ method Resize operation completed with no errors. Before deleting the old disk, carefully check that the resized disk boots and works correctly. [root@kvmhost ~]# virt-filesystems --long --parts --blkdevs -h -a /var/lib/libvirt/images/centos7-new.qcow2 Name Type MBR Size Parent /dev/sda1 partition 83 1.0G /dev/sda /dev/sda2 partition 8e 9.0G /dev/sda /dev/sda device - 10G -
仮想マシンの変更
仮想マシンが使用するディスクイメージを新しい方に変更して起動。
[root@kvmhost ~]# virsh edit centos7 [root@kvmhost ~]# virsh start centos7
変更後のゲストの状態
[root@guest ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 988M 0 988M 0% /dev tmpfs 1000M 0 1000M 0% /dev/shm tmpfs 1000M 8.5M 992M 1% /run tmpfs 1000M 0 1000M 0% /sys/fs/cgroup /dev/mapper/centos-root 8.2G 1.3G 7.0G 15% / /dev/vda1 1014M 137M 878M 14% /boot tmpfs 200M 0 200M 0% /run/user/0 [root@guest ~]# lvdisplay /dev/centos/root --- Logical volume --- LV Path /dev/centos/root LV Name root VG Name centos LV UUID g8yMUy-1eYI-BIN2-9khy-7cjA-n8fn-dOUcRa LV Write Access read/write LV Creation host, time localhost, 2022-04-29 05:14:00 +0900 LV Status available # open 1 LV Size <8.20 GiB Current LE 2098 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0