一、目的

在使用CentOS6.5版本linux系统的时候，发现根目录(/)的空间不是很充足，而其他目录空间有很大的空闲，所以本文主要是针对现在已有的空间进行调整。首先，先来查看一下系统的空间分配情况：

[root@innoplay01 ~]# lsb_release -a
LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 6.5 (Final)
Release: 6.5

Codename: Final

[root@innoplay01 java]# df -h
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/vg_innoplay01-lv_root   50G  2.0G   45G   5% /
tmpfs                              3.9G     0  3.9G   0% /dev/shm
/dev/sda1                          485M   40M  421M   9% /boot
/dev/mapper/vg_innoplay01-lv_home  860G  200M  816G   1% /home

下面的详细步骤部分将从/dev/mapper/vg_innoplay01-lv_home 分区下取出661G的空间添加到/dev/mapper/vg_innoplay01-lv_root 分区上去。

卸载/dev/mapper/vg_innoplay01-lv_home分区:


[root@innoplay01 java]# umount /home


此时在用df命令查看将会发现/home目录已经看不见了，如下所示：


[root@innoplay01 java]# df -h
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/vg_innoplay01-lv_root   50G  2.0G   45G   5% /
tmpfs                              3.9G     0  3.9G   0% /dev/shm
/dev/sda1                          485M   40M  421M   9% /boot



从新设定/dev/mapper/vg_innoplay01-lv_home的大小:


resize2fs -p /dev/mapper/vg_innoplay01-lv_home 210G

[root@innoplay01 java]#  resize2fs -p /dev/mapper/vg_innoplay01-lv_home 210G
resize2fs 1.41.12 (17-May-2010)
Please run 'e2fsck -f /dev/mapper/vg_innoplay01-lv_home' first.

依照提示执行：

e2fsck -f /dev/mapper/vg_innoplay01-lv_home

[root@innoplay01 java]# e2fsck -f /dev/mapper/vg_innoplay01-lv_home
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mapper/vg_innoplay01-lv_home: 11/57237504 files (0.0% non-contiguous), 3643567/228918272 blocks
[root@innoplay01 java]# resize2fs -p /dev/mapper/vg_innoplay01-lv_home 210G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/vg_innoplay01-lv_home to 55050240 (4k) blocks.
Begin pass 2 (max = 32768)
Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 6987)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/vg_innoplay01-lv_home is now 55050240 blocks long.






检查是否成功：


[root@innoplay01 java]# mount /home
[root@innoplay01 java]# df -h
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/vg_innoplay01-lv_root   50G  2.0G   45G   5% /
tmpfs                              3.9G     0  3.9G   0% /dev/shm
/dev/sda1                          485M   40M  421M   9% /boot
/dev/mapper/vg_innoplay01-lv_home  207G  188M  197G   1% /home

将/dev/mapper/vg_innoplay01-lv_home逻辑分区减小到指定大小：

lvreduce -L 210G /dev/mapper/vg_innoplay01-lv_home

[root@innoplay01 java]# lvreduce -L 210G /dev/mapper/vg_innoplay01-lv_home
  WARNING: Reducing active and open logical volume to 210.00 GiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv_home? [y/n]: y
  Reducing logical volume lv_home to 210.00 GiB
  Logical volume lv_home successfully resized

  查询卷组的信息：
  vgdisplay  

  [root@innoplay01 java]# vgdisplay
  --- Volume group ---
  VG Name               vg_innoplay01
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               931.02 GiB
  PE Size               4.00 MiB
  Total PE              238341
  Alloc PE / Size       68548 / 267.77 GiB
  Free  PE / Size       169793 / 663.25 GiB
  VG UUID               SyMjnp-iGwM-MkT1-UBUM-rSx8-hviz-EzTUEr

  Free PE / Size指定的应该是现在可在分配的空间。

  增加/dev/mapper/vg_innoplay01-lv_root分区的大小:

  lvextend -L +661.00G /dev/mapper/vg_innoplay01-lv_root

  [root@innoplay01 java]#  lvextend -L +661.00G /dev/mapper/vg_innoplay01-lv_root
  Extending logical volume lv_root to 711.00 GiB
  Logical volume lv_root successfully resized


  从新设定该分区的大小：
  resize2fs -p /dev/mapper/vg_innoplay01-lv_root

  [root@innoplay01 java]# resize2fs -p /dev/mapper/vg_innoplay01-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_innoplay01-lv_root is mounted on /; on-line resizing required
old desc_blocks = 18, new_desc_blocks = 45
Performing an on-line resize of /dev/mapper/vg_innoplay01-lv_root to 186384384 (4k) blocks.
The filesystem on /dev/mapper/vg_innoplay01-lv_root is now 186384384 blocks long.


再次查看分区大小:
[root@innoplay01 java]# df -h
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/vg_innoplay01-lv_root  700G  2.0G  663G   1% /
tmpfs                              3.9G     0  3.9G   0% /dev/shm
/dev/sda1                          485M   40M  421M   9% /boot
/dev/mapper/vg_innoplay01-lv_home  207G  188M  197G   1% /home

注意点：

1、在卸载/home目录的时候失败，可先执行如下fuser命令，然后再umount即可：fuser -m /home ；

2、设定完lv_home的大小，再次mount该分区时，发现用df命令无法看到给分区，此时只要在mount一次即可；

3、在设定lv_root的大小时，不要把Free PE / Size的空间全部都用上，这很可能会出现Free PE空间不足的现象，建议保留一点Free PE的空间。