虛擬機磁盤在創建時就固定了大小，后期要新增磁盤空間的話，只能擴容當前分區空間或者新增磁盤。

一、當前硬盤擴容

kvm虛擬機磁盤格式分為raw和qcow2兩種，擴容方式命令相同，區別是后綴名

• 查看當前硬盤空間并擴容鏡像磁盤空間

# qemu-img info vm5.qcow2 image: vm5.qcow2 file format: qcow2 virtual size: 20G (21474836480 bytes) disk size: 1.6G cluster_size: 65536 Format specific information:compat: 1.1lazy refcounts: true# qemu-img resize /data/kvm/vm5.qcow2 +10G //鏡像空間加10G Image resized.# qemu-img info vm5.qcow2 image: vm5.qcow2 file format: qcow2 virtual size: 30G (32212254720 bytes) disk size: 1.6G cluster_size: 65536 Format specific information:compat: 1.1lazy refcounts: true

• 重啟虛擬機，查看磁盤空間已經調整，掛載空間還需要調整

# virsh shutdown vm5 # virsh start vm5 # virsh console vm5 # df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-lv_root19G 697M 17G 4% / tmpfs 246M 0 246M 0% /dev/shm /dev/vda1 477M 34M 418M 8% /boot# fdisk -l Disk /dev/vda: 32.2 GB, 32212254720 bytes 16 heads, 63 sectors/track, 62415 cylinders Units = cylinders of 1008 * 512 = 516096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00070304Device Boot Start End Blocks Id System /dev/vda1 * 3 1018 512000 83 Linux /dev/vda2 1018 41611 20458496 8e Linux LVMDisk /dev/mapper/VolGroup-lv_root: 18.8 GB, 18798870528 bytes 255 heads, 63 sectors/track, 2285 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000Disk /dev/mapper/VolGroup-lv_swap: 2147 MB, 2147483648 bytes 255 heads, 63 sectors/track, 261 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

• 新增的空間進行分區

# fdisk /dev/vda WARNING: DOS-compatible mode is deprecated. It's strongly recommended toswitch off the mode (command 'c') and change display units tosectors (command 'u').Command (m for help): pDisk /dev/vda: 32.2 GB, 32212254720 bytes 16 heads, 63 sectors/track, 62415 cylinders Units = cylinders of 1008 * 512 = 516096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00070304Device Boot Start End Blocks Id System /dev/vda1 * 3 1018 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/vda2 1018 41611 20458496 8e Linux LVM Partition 2 does not end on cylinder boundary.Command (m for help): n //新增分區 Command actione extendedp primary partition (1-4) p //主分區 Partition number (1-4): 3 First cylinder (1-62415, default 1): 41611 Last cylinder, +cylinders or +size{K,M,G} (41611-62415, default 62415): Using default value 62415Command (m for help): pDisk /dev/vda: 32.2 GB, 32212254720 bytes 16 heads, 63 sectors/track, 62415 cylinders Units = cylinders of 1008 * 512 = 516096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00070304Device Boot Start End Blocks Id System /dev/vda1 * 3 1018 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/vda2 1018 41611 20458496 8e Linux LVM Partition 2 does not end on cylinder boundary. /dev/vda3 41611 62415 10485640 83 LinuxCommand (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.

• 把 /dev/vda3 加入到 lvm 里面去，如 /dev/vda3 設備不存在則重啟虛擬機即可

# pvcreate /dev/vda3 //創建物理卷Physical volume "/dev/vda3" successfully created # pvs //查看卷PV VG Fmt Attr PSize PFree /dev/vda2 VolGroup lvm2 a--u 19.51g 0 /dev/vda3 lvm2 ---- 10.00g 10.00g # vgextend VolGroup /dev/vda3 //VolGroup虛擬卷擴展，vda3加入到VolGroup(這個名字從上面pvs中VG字段獲取)Volume group "VolGroup" successfully extended # pvsPV VG Fmt Attr PSize PFree /dev/vda2 VolGroup lvm2 a--u 19.51g 0 /dev/vda3 VolGroup lvm2 a--u 10.00g 10.00g # vgsVG #PV #LV #SN Attr VSize VFree VolGroup 2 2 0 wz--n- 29.50g 10.00g # lvs //查看邏輯卷LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convertlv_root VolGroup -wi-ao---- 17.51g lv_swap VolGroup -wi-ao---- 2.00g # df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-lv_root18G 696M 16G 5% / tmpfs 939M 0 939M 0% /dev/shm /dev/vda1 477M 40M 413M 9% /boot # lvextend -l +100%FREE /dev/mapper/VolGroup-lv_root //擴展卷,卷名從 df -h 獲取Size of logical volume VolGroup/lv_root changed from 17.51 GiB (4482 extents) to 27.50 GiB (7041 extents).Logical volume lv_root successfully resized. # df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-lv_root18G 696M 16G 5% / tmpfs 939M 0 939M 0% /dev/shm /dev/vda1 477M 40M 413M 9% /boot

• 使用 resize2fs 或 xfs_growfs 命令進行最后擴容

# resize2fs /dev/mapper/VolGroup-lv_root resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/mapper/VolGroup-lv_root is mounted on /; on-line resizing required old desc_blocks = 2, new_desc_blocks = 2 Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 7209984 (4k) blocks. The filesystem on /dev/mapper/VolGroup-lv_root is now 7209984 blocks long.# xfs (CentOS 7)文件系統格式使用 xfs_growfs 命令擴容 # xfs_growfs /dev/mapper/VolGroup-lv_root# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-lv_root27G 696M 25G 3% / tmpfs 939M 0 939M 0% /dev/shm /dev/vda1 477M 40M 413M 9% /boot

二、新增硬盤

• 創建磁盤

# qemu-img create -f qcow2 vm5_2.qcow2 5G Formatting 'vm5_2.qcow2', fmt=qcow2 size=5368709120 encryption=off cluster_size=65536 lazy_refcounts=off

• 關閉虛擬機并修改配置文件，添加如下配置

# virsh destroy vm5 Domain vm5 destroyed # virsh edit vm5 ......<disk type='file' device='disk'><driver name='qemu' type='qcow2' cache='none'/><source file='/data/kvm/vm5_2.qcow2'/><target dev='vdb' bus='virtio'/><address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/></disk> ......

• 開機虛擬機，格式化硬盤并掛載

# virsh start vm5 # virsh console vm5 # mkfs.ext4 /dev/vdb # mount /dev/vdb /data

總結

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