摘自《VM虚拟机中Linux扩展根分区空间》，百度文库链接，如有侵权，请联系告知。

必须是基于“卷管理”的才能够扩展分区。

[root@SQL2 ~]# lvdisplay

如果能看到“物理卷”和“逻辑卷”，说明OK。

1.VMware扩展
在关机状态下，点击“硬盘->扩展”，然后输入大小（从50GB改到80GB），点击确定。

2.开启虚拟机

[root@SQL2 ~]# df -h

发现没有改变

3.用命令查看sda已经扩展

[root@SQL2 ~]# fdisk /dev/sda 
Welcome to fdisk (util-linux 2.23.2).   

Changes will remain in memory only, until you decide to write them. 
Be careful before using the write command.    

Command (m for help): p   

Disk /dev/sda: 85.9 GB, 85899345920 bytes, 167772160 sectors

4.查看lvm状态

[root@SQL2 ~]# pvs
    PV         VG     Fmt  Attr PSize  PFree
    /dev/sda2  centos lvm2 a--  49.51g 44.00m
[root@SQL2 ~]# vgs
    VG     #PV #LV #SN Attr   VSize  VFree 
    centos   1   2   0 wz--n- 49.51g 44.00m 
[root@SQL2 ~]# lvs
    LV   VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert  
    root centos -wi-ao---- 45.59g
    swap centos -wi-ao----  3.88g

5.生成分区/dev/sda3

[root@SQL2 ~]# fdisk /dev/sda
 Welcome to fdisk (util-linux 2.23.2).

 Changes will remain in memory only, until you decide to write them. 
 Be careful before using the write command.    

 Command (m for help): p   

 Disk /dev/sda: 85.9 GB, 85899345920 bytes, 167772160 sectors 
 Units = sectors of 1 * 512 = 512 bytes  
 Sector size (logical/physical): 512 bytes / 512 bytes 
 I/O size (minimum/optimal): 512 bytes / 512 bytes 
 Disk label type: dos  
 Disk identifier: 0x0006069d      

 Device Boot      Start         End      Blocks   Id  System 
 /dev/sda1   *        2048     1026047      512000   83  Linux  
 /dev/sda2         1026048   104857599    51915776   8e  Linux LVM   

 Command (m for help): n 
 Partition type:  
 p   primary (2 primary, 0 extended, 2 free) 
 e   extended  
 Select (default p): p    
 Partition number (3,4, default 3): 3  
 First sector (104857600-167772159, default 104857600): #回车 
 Using default value 104857600  
 Last sector, +sectors or +size{K,M,G} (104857600-167772159, default 167772159): #回车 
 Using default value 167772159  
 Partition 3 of type Linux and of size 30 GiB is set   

 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.

6.重读磁盘分区

[root@SQL2 ~]# partprobe

如果不行就重启reboot

7.格式化/dev/sda3

[root@SQL2 ~]# mkfs.ext4 /dev/sda3 
mke2fs 1.42.9 (28-Dec-2013) 
Filesystem label= 
OS type: Linux  
Block size=4096 (log=2) 
Fragment size=4096 (log=2)  
Stride=0 blocks, Stripe width=0 blocks 
1966080 inodes, 7864320 blocks  
393216 blocks (5.00%) reserved for the super user 
First data block=0  
Maximum filesystem blocks=2155872256 
240 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, 1605632, 2654208,          
    4096000   
Allocating group tables: done                             
Writing inode tables: done                             
Creating journal (32768 blocks): done  
Writing superblocks and filesystem accounting information: done

8.lvm 扩容

[root@SQL2 ~]#  pvcreate  /dev/sda3  
WARNING: ext4 signature detected on /dev/sda3 at offset 1080. Wipe it? [y/n]: y 
Wiping ext4 signature on /dev/sda3.    
Physical volume "/dev/sda3" successfully created

[root@SQL2 ~]# pvs    
PV         VG     Fmt  Attr PSize  PFree     
/dev/sda2  centos lvm2 a--  49.51g 44.00m  #标红为组名，下步会用到   
/dev/sda3         lvm2 ---  30.00g 30.00g

[root@SQL2 ~]# vgextend centos /dev/sda3  #(注意组名)   
Volume group "centos" successfully extended

#此处+29.9表示大约扩展30G空间，若是此处设置为80G 也是可行，表示扩展后总容量 
[root@SQL2 ~]# lvextend -L +29.9G /dev/mapper/centos-root  /dev/sda3   
Rounding size to boundary between physical extents: 29.90 GiB    
Size of logical volume centos/root changed from 45.59 GiB (11671 extents) to 75.49 GiB (19326 extents).    
Logical volume root successfully resized.

#若此处报错，可以不管，执行下个resize2fs命令，若正确，可忽略resize2fs命令 
[root@SQL2 ~]#  resize2fs /dev/mapper/centos-root 
resize2fs 1.42.9 (28-Dec-2013)  
resize2fs: Bad magic number in super-block while trying to open /dev/mapper/centos-root Couldn't find valid filesystem superblock.   

[root@SQL2 ~]#  resize2fs /dev/mapper/centos-root 
resize2fs 1.42.9 (28-Dec-2013)  
resize2fs: Bad magic number in super-block while trying to open /dev/mapper/centos-root Couldn't find valid filesystem superblock. 

[root@SQL2 ~]# xfs_growfs /dev/mapper/centos-root  
meta-data=/dev/mapper/centos-root isize=256    agcount=4, agsize=2987776 blks
          =                       sectsz=512   attr=2, projid32bit=1          
data     =                       bsize=4096   blocks=11951104, imaxpct=25          
         =                       sunit=0      swidth=0 blks 
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0 
log      =internal               bsize=4096   blocks=5835, version=2
          =                       sectsz=512   sunit=0 blks, lazy-count=1 
realtime =none                   extsz=4096   blocks=0, rtextents=0 
data blocks changed from 11951104 to 19789824

[root@SQL2 ~]# df -h  
Filesystem               Size  Used Avail Use% Mounted on 
/dev/mapper/centos-root   76G   12G   65G  15% /  
devtmpfs                 1.9G     0  1.9G   0% /dev  
tmpfs                    1.9G   84K  1.9G   1% /dev/shm 
tmpfs                    1.9G  9.0M  1.9G   1% /run  
tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/sda1                497M  159M  339M  32% /boot  
tmpfs                    379M   16K  379M   1% /run/user/42 
tmpfs                    379M     0  379M   0% /run/user/0

已经成功。