KVM虚拟机添加虚拟磁盘

step1：创建一个qcow2格式的磁盘镜像

[root@kvm ~]# qemu-img create -f qcow2 /kvm/centos1_1.qcow2 5G
Formatting '/kvm/centos1_1.qcow2', fmt=qcow2 size=5368709120 encryption=off cluster_size=65536

[root@kvm ~]# virsh destroy centos1
Domain centos1 destroyed

step2：编辑/etc/libvirt/qemu/centos1.xml 增加磁盘模块

[root@kvm ~]# vim /etc/libvirt/qemu/centos1.xml
或者
[root@kvm ~]# virsh edit centos1
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2' cache='none'/>
<source file='/kvm/centos1_1.qcow2'/>
<target dev='vdb' bus='virtio'/>
</disk>

开启虚拟机

[root@kvm ~]# virsh start centos1
[root@kvm ~]# virsh console centos1

step3：分区

[root@localhost ~]# fdisk -l
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: 0x000e5856
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
Disk /dev/vdb: 5368 MB, 5368709120 bytes
16 heads, 63 sectors/track, 10402 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: 0x00000000
Disk /dev/mapper/VolGroup-lv_root: 14.5 GB, 14533263360 bytes
255 heads, 63 sectors/track, 1766 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
Disk /dev/mapper/VolGroup-lv_swap: 1040 MB, 1040187392 bytes
255 heads, 63 sectors/track, 126 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

分区

[root@localhost ~]# fdisk /dev/vdb
Command (m for help): p
Command (m for help): n
Command action
e   extended
p   primary partition (1-4)
p
Partition number (1-4):
Value out of range.
Partition number (1-4): 1
First cylinder (1-10402, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-10402, default 10402):
Using default value 10402
Command (m for help): p
Disk /dev/vdb: 5368 MB, 5368709120 bytes
16 heads, 63 sectors/track, 10402 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: 0x3d00f46a
Device Boot      Start         End      Blocks   Id  System
/dev/vdb1               1       10402     5242576+  83  Linux
Command (m for help): w
The partition table has been altered!

[root@localhost ~]# partx /dev/vdb
# 1:        63- 10485215 ( 10485153 sectors,   5368 MB)
# 2:         0-       -1 (        0 sectors,      0 MB)
# 3:         0-       -1 (        0 sectors,      0 MB)
# 4:         0-       -1 (        0 sectors,      0 MB)

[root@localhost ~]# ll /dev/vdb*
brw-rw----. 1 root disk 252, 16 Jan 17 01:22 /dev/vdb
brw-rw----. 1 root disk 252, 17 Jan 17 01:22 /dev/vdb1

格式化

[root@localhost ~]# mkfs.ext4 /dev/vdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
327680 inodes, 1310644 blocks
65532 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 27 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

挂载/自动挂载

[root@localhost ~]# mkdir /data
[root@localhost ~]# mount /dev/vdb1 /data/
EXT4-fs (vdb1): mounted filesystem with ordered data mode. Opts:

[root@localhost ~]# df -Th
Filesystem           Type   Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
ext4    14G  685M   12G   6% /
tmpfs                tmpfs  246M     0  246M   0% /dev/shm
/dev/vda1            ext4   477M   33M  419M   8% /boot
/dev/vdb1            ext4   4.8G   10M  4.6G   1% /data

[root@localhost ~]# vi /etc/fstab
/dev/vdb1               /data                   ext4    defaults        0 0