KVM虛擬磁盤擴容

1、磁盤擴容分為raw和qcow2兩種擴容方式，命令相同，區別是后綴名

[root@daixuan ~]# qemu-img info /data/daixuan1.qcow2?//本身只有9G

p_w_picpath: /data/daixuan1.qcow2

file format: qcow2

virtual size: 10G (10737418240 bytes)

disk size: 10G

cluster_size: 65536

[root@daixuan ~]# qemu-img resize /data/daixuan1.qcow2 +5G ?//加5G

Image resized.

[root@daixuan ~]# qemu-img info /data/daixuan1.qcow2 //查看已經+5G，登錄后fdisk -l還是10G

p_w_picpath: /data/daixuan1.qcow2

file format: qcow2

virtual size: 15G (16106127360 bytes)

如果需要真正生效，需要destroy，之后start，把配置重新加載

[root@daixuan ~]# virsh destroy daixuan1

[root@daixuan ~]# virsh start daixuan1

[root@daixuan ~]# virsh console daixuan1

fdisk -l ? 列出系統中所有的磁盤設備和分區表，這里磁盤設備容量已經增加5G

[root@localhost ~]# fdisk -l

Disk /dev/vda: 16.1 GB, 16106127360 bytes

2、但是磁盤掛載的空間并沒有增加，依然是8.3G

[root@localhost ~]# df -h //查看可用磁盤總容量和使用容量

Filesystem ?Size ?Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root 8.3G ?685M ?7.2G ? 9% /

tmpfs ? ? ? ? ? ? ? ?246M ? ? 0 ?246M ? 0% /dev/shm

/dev/vda1 ? ? ? ? ? ? 477M ? 33M ?419M ? 8% /boot

(1)因為新增加的空間還沒有劃分使用，所以要繼續分區：

[root@localhost ~]# fdisk /dev/vda

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to

switch off the mode (command 'c') and change display units to

sectors (command 'u').

Command (m for help): p

Disk /dev/vda: 16.1 GB, 16106127360 bytes

16 heads, 63 sectors/track, 31207 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: 0x000dca27

Device Boot ? ? ?Start ? ? ? ? End ? ? ?Blocks ? Id ?System

/dev/vda1 ? * ? ? ? ? ? 3 ? ? ? ?1018 ? ? ?512000 ? 83 ?Linux

Partition 1 does not end on cylinder boundary.

/dev/vda2 ? ? ? ? ? ?1018 ? ? ? 20806 ? ? 9972736 ? 8e ?Linux LVM

Partition 2 does not end on cylinder boundary.

Command (m for help): n

Command action

e ? extended

p ? primary partition (1-4)

p

Partition number (1-4): 3

First cylinder (1-31207, default 1): 20807

Last cylinder, +cylinders or +size{K,M,G} (20807-31207, default 31207): 31207

Command (m for help): p

Disk /dev/vda: 16.1 GB, 16106127360 bytes

16 heads, 63 sectors/track, 31207 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: 0x000dca27

Device Boot ? ? ?Start ? ? ? ? End ? ? ?Blocks ? Id ?System

/dev/vda1 ? * ? ? ? ? ? 3 ? ? ? ?1018 ? ? ?512000 ? 83 ?Linux

Partition 1 does not end on cylinder boundary.

/dev/vda2 ? ? ? ? ? ?1018 ? ? ? 20806 ? ? 9972736 ? 8e ?Linux LVM

Partition 2 does not end on cylinder boundary.

/dev/vda3 ? ? ? ? ? 20807 ? ? ? 31207 ? ? 5242104 ? 83 ?Linux

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.

(2)然后再把這個/dev/vda3 加入到lvm里面去：

[root@localhost ~]# ls /dev/vda3?//如果沒有這個分區，需要重啟一下

[root@localhost ~]# reboot

[root@localhost ~]# pvcreate?/dev/vda3 ?//創建物理卷

Physical volume "/dev/vda3" successfully created

[root@localhost ~]# pvs //查看卷

PV ? ? ? ? VG ? ? ? Fmt ?Attr PSize PFree

/dev/vda2 ?VolGroup ? ? lvm2 a-- ?9.51g ?0

/dev/vda3 ? ? ? ? ? ?lvm2 --- ?5.00g ?5.00g

[root@localhost ~]# vgextend VolGroup /dev/vda3 ?//VolGroup虛擬卷擴展，vda3加入到Vol

Volume group "VolGroup" successfully extended

[root@localhost ~]# pvs

PV ? ? ? ? VG ? ? ? Fmt ?Attr PSize PFree

/dev/vda2 ?VolGroup lvm2 a-- ?9.51g ? ?0

/dev/vda3 ?VolGroup lvm2 a-- ?5.00g ? ?0

[root@localhost ~]# vgs ? ?//VFree中5G

VG ? ? ? #PV #LV #SN Attr ? VSize ?VFree

VolGroup ? 2 ? 2 ? 0 wz--n- 14.50g? 5.00g

如何把5G加入到lv_root中？

[root@localhost ~]# lvs //查看邏輯卷

LV ? ?VG ?Attr ? ?LSize ? Pool Origin Data% ?Meta% ?Move Log Cpy%Sync Convert

lv_root VolGroup -wi-ao---- ? 8.54g

lv_swap VolGroup -wi-ao---- 992.00m

[root@localhost ~]# lvextend -l +100%FREE /dev/VolGroup/lv_root ?//擴展卷

Size of logical volume VolGroup/lv_root changed from 8.54 GiB (2186 extents) to 13.54 GiB (3465 extents).

Logical volume lv_root successfully resized

[root@localhost ~]# df -h

Filesystem ? ? ? ? ? ?Size ?Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root 8.3G ?685M ?7.2G ? 9% /

tmpfs ? ? ? ? ? ? ? ?246M ? ? 0 ?246M ? 0% /dev/shm

/dev/vda1 ? ? ? ? ? ? ?477M ? 33M ?419M ? 8% /boot

[root@localhost ~]# resize2fs/dev/VolGroup/lv_root

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/VolGroup/lv_root is mounted on /; on-line resizing required

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of /dev/VolGroup/lv_root to 3548160 (4k) blocks.

The filesystem on /dev/VolGroup/lv_root is now 3548160 blocks long.

[root@localhost ~]# df -h

Filesystem ? ? ? ? ? ? ?Size ?Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root 14G?687M ? 12G ? 6% /

tmpfs ? ? ? ? ? ? ? ? 246M ? ? 0 ?246M ? 0% /dev/shm

/dev/vda1 ? ? ? ? ? ? ?477M ? 33M ?419M ? 8% /boot

如果提示 This p_w_picpath format does not support resize, 檢查一下你qemu-img create的時候，是否有加 preallocation=metadata 選項，如果有，就不能resize了。

(3)另外，如果是增加磁盤，思路是創建磁盤： qemu-img create -f qcow2 ?/data/daixuan1_2.qcow2 5G關閉虛擬機： virsh destroy daixuan1編輯配置文件： virsh edit daixuan1

復制增加如下：注意是vdb，qcow2

開啟虛擬機：virsh start daixuan1進入虛擬機：virsh console daixuan1分區： fdisk /dev/vdb格式化：mkfs.ext4 /dev/vdb

掛載：vim /etc/fstab，添加一行：/dev/vdb ?/mnt ?ext4 ? defaults ? ?0 0

mount -a 然后mnt就可以使用了

[root@localhost ~]# cd /mnt

[root@localhost mnt]# touch 23.txt

當然也可以按照上面的思路把 /dev/vdb 加入到 lvm里面去，測試成功，這里省略步驟注： raw格式步驟基本上和qcow2一樣。如果提示 This p_w_picpath format does not support resize, 檢查一下你qemu-img create的時候，是否有加??preallocation=metadata 選項，如果有，就不能resize了。

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