CentOS7 KVM虚拟化之虚拟机根分区扩容

一、扩展虚拟机磁盘

1.关闭虚拟机

virsh shutdown web01

2.查看虚拟机磁盘当前大小

[root@KVM01 ~]# qemu-img info /vm-images/vm1-clone.img
image: /vm-images/vm1-clone.img
file format: qcow2
virtual size: 10G (11206127360 bytes)
disk size: 1.7G
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: true

3.扩展磁盘大小

qemu-img resize /vm-images/vm1-clone.img +5G

4.再次查看虚拟机磁盘当前大小

[root@kvm01 ~]# qemu-img info /vm-images/vm1-clone.img
image: /vm-images/vm1-clone.img
file format: qcow2
virtual size: 15G (16106127360 bytes)
disk size: 1.7G
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: true

二、扩展虚拟机根分区

1.查看当前分区状况，可以看到磁盘/dev/vda大小变化

[root@localhost ~]# fdisk -l

Disk /dev/vda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1          25      200781   83  Linux
/dev/vda2              26         156     1052257+  82  Linux swap / Solaris
/dev/vda3             157        1305     9229342+  83  Linux      #注意这里起始cylinder 是157，起始cylinder 绝对不可以改，否则会破坏原分区的数据。

2.扩展根分区

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

The number of cylinders for this disk is set to 1958.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/vda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1          25      200781   83  Linux
/dev/vda2              26         156     1052257+  82  Linux swap / Solaris
/dev/vda3             157        1305     9229342+  83  Linux

Command (m for help): d            #删除原本分区

Partition number (1-4): 3                    #之前根/分区是多少就输入几，这里是/dev/vda3

Command (m for help): p

Disk /dev/vda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           1          25      200781   83  Linux
/dev/vda2              26         156     1052257+  82  Linux swap / Solaris

Command (m for help): n
Command action
e   extended
p   primary partition (1-4)
Select (default p): p
Partition number (1-4): 3                  #之前是多少，这里还输入多少
First cylinder (157-1958, default 157):#直接回车
Using default value 157
Last cylinder or +size or +sizeM or +sizeK (157-1958, default 1958):                      #直接回车，由之前1305，扩为1958
Using default value 1958

Command (m for help): w                #保存
The partition table has been altered!

Calling ioctl() to re-read partition table.

The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

三、重启虚拟机，完成根分区扩容

执行如下命令，重启系统

[root@localhost ~]#reboot

重启后执行如下命令，刷新磁盘

[root@localhost ~]# xfs_growfs /dev/vda1


meta-data=/dev/vda1 isize=512 agcount=7, agsize=655296 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=3931904, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0

四、验证

查看当前磁盘状态

[root@localhost ~]# df -h
文件系统              容量  已用 可用 已用% 挂载点
/dev/vda3              14G  1.3G   12G  11% /
/dev/vda1             190M   12M  169M   7% /boot
tmpfs                 379M     0  379M   0% /dev/shm

如上，完成根分区扩容

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