kvm扩容home目录

心已赠人 2023-06-19 14:30 26阅读 0赞

**KVM虚拟磁盘扩容**

**1、磁盘扩容分为raw和qcow2两种扩容方式，命令相同，区别是后缀名**

\[root@daixuan ~\]\# 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 //查看已经+5G，登录后fdisk -l还是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，把配置重新加载

\[root@daixuan ~\]\# virsh destroy daixuan1

\[root@daixuan ~\]\# virsh start daixuan1

\[root@daixuan ~\]\# virsh console daixuan1

fdisk -l   列出系统中所有的磁盘设备和分区表，这里磁盘设备容量已经增加5G

\[root@localhost ~\]\# fdisk -l

Disk /dev/vda: 16.1 GB, 16106127360 bytes

**2、但是磁盘挂载的空间并没有增加，依然是8.3G**

\[root@localhost ~\]\# df -h //查看可用磁盘总容量和使用容量

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）因为新增加的空间还没有划分使用，所以要继续分区：**

\[root@localhost ~\]\# 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)

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）然后再把这个/dev/vda3 加入到lvm里面去：**

\[root@localhost ~\]\# ls /dev/vda3 //如果没有这个分区，需要重启一下

\[root@localhost ~\]\# reboot

\[root@localhost ~\]\# pvcreate /dev/vda3  //创建物理卷

Physical volume "/dev/vda3" successfully created

\[root@localhost ~\]\# pvs //查看卷    把新建的vda加入原有的vg里

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虚拟卷扩展，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 //查看逻辑卷

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  //扩展卷   就是要扩展的全路径

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   （查看文件系统）  如果是xfs\_growfs /dev/mapper/rhel-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, 检查一下你qemu-img create的时候，是否有加 preallocation=metadata 选项，如果有，就不能resize了。

**（3）另外，如果是增加磁盘，思路是**  
创建磁盘： qemu-img create -f qcow2  /data/daixuan1\_2.qcow2 5G  
关闭虚拟机： virsh destroy daixuan1  
编辑配置文件： virsh edit daixuan1

复制增加如下：注意是vdb，qcow2

开启虚拟机：virsh start daixuan1  
进入虚拟机：virsh console daixuan1  
分区： fdisk /dev/vdb  
格式化：mkfs.ext4 /dev/vdb

挂载：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

当然也可以按照上面的思路把 /dev/vdb 加入到 lvm里面去，测试成功，这里省略步骤  
  
注： raw格式  
步骤基本上和qcow2一样。如果提示 This p\_w\_picpath format does not support resize, 检查一下你qemu-img create的时候，是否有加  preallocation=metadata 选项，如果有，就不能resize了。