CentOS环境下下调整home和根分区大小

项目建设方给提供了3台CentOS的服务器，连接进去之后发现磁盘空间很大，但是都放在了home目录下，所以需要调整一下。

1、查看磁盘使用情况

[root@CentOS ~]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root   50G  9.9G   37G  22% /
tmpfs                          3.9G   72K  3.9G   1% /dev/shm
/dev/sda1                      485M   40M  421M   9% /boot
/dev/mapper/vg_centos-lv_home  439G  200M  417G   1% /home

2、卸载/home

[root@CentOS ~]# umount /home
[root@CentOS ~]#
[root@CentOS ~]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root   50G   11G   37G  22% /
tmpfs                          3.9G   72K  3.9G   1% /dev/shm
/dev/sda1                      485M   40M  421M   9% /boot

3、调整分区大小

[root@CentOS ~]# resize2fs -p /dev/mapper/vg_centos-lv_home 40G
resize2fs 1.41.12 (17-May-2010)
请先运行 'e2fsck -f /dev/mapper/vg_centos-lv_home'.

[root@CentOS ~]# e2fsck -f /dev/mapper/vg_centos-lv_home
e2fsck 1.41.12 (17-May-2010)
第一步: 检查inode,块,和大小
第二步: 检查目录结构
第3步: 检查目录连接性
Pass 4: Checking reference counts
第5步: 检查簇概要信息
/dev/mapper/vg_centos-lv_home: 163/29212672 files (0.0% non-contiguous), 1884450/116819968 blocks

再次执行

[root@CentOS ~]# resize2fs -p /dev/mapper/vg_centos-lv_home 40G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/vg_centos-lv_home to 10485760 (4k) blocks.
Begin pass 2 (max = 32975)
正在重定位块            XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 3566)
正在扫描inode表          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 84)
正在更新inode引用       XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/vg_centos-lv_home is now 10485760 blocks long.

4、挂载/home

[root@CentOS ~]# mount /home

查看磁盘使用情况：

[root@CentOS ~]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root   50G   11G   37G  22% /
tmpfs                          3.9G   72K  3.9G   1% /dev/shm
/dev/sda1                      485M   40M  421M   9% /boot
/dev/mapper/vg_centos-lv_home   40G  178M   38G   1% /home

5、设置空闲空间

[root@CentOS ~]# lvreduce -L 40G /dev/mapper/vg_centos-lv_home
WARNING: Reducing active and open logical volume to 40.00 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 40.00 GiB
Logical volume lv_home successfully resized

使用lvreduce指令用于减少LVM逻辑卷占用的空间大小。可能会删除逻辑卷上已有的数据，所以在操作前必须进行确认。记得输入 “y”
[root@localhost ~]# lvreduce -L 20G /dev/mapper/VolGroup-lv_home
注：lvreduce -L 20G的意思为设置当前文件系统为20G，如果lvreduce -l 20G是指从当前文件系统上减少20G
使用lvreduce减小逻辑卷的大小。注意：减小后的大小不能小于文件的大小，否则会丢失数据。

可以使用vgdisplay命令等查看一下可以操作的大小。也可以是用fdisk -l命令查看详细信息。
[root@localhost ~]# vgdisplay
注：vgdisplay为显示LVM卷组的元数据信息。

6、将空闲空间挂载到根目录下

[root@CentOS ~]# vgdisplay
--- Volume group ---
VG Name               vg_centos
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               499.51 GiB
PE Size               4.00 MiB
Total PE              127874
Alloc PE / Size       24032 / 93.88 GiB
Free  PE / Size       103842 / 405.63 GiB
VG UUID               ASX7Lb-Y0p6-YCGH-hNYp-ewdK-iFse-fq7uWw

[root@CentOS ~]#
[root@CentOS ~]#
[root@CentOS ~]# lvextend -L +400G /dev/mapper/vg_centos-lv_root
Extending logical volume lv_root to 450.00 GiB
Logical volume lv_root successfully resized
[root@CentOS ~]#
[root@CentOS ~]#
[root@CentOS ~]# vgdisplay
--- Volume group ---
VG Name               vg_centos
System ID
Format                lvm2
Metadata Areas        1
Metadata Sequence No  6
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               499.51 GiB
PE Size               4.00 MiB
Total PE              127874
Alloc PE / Size       126432 / 493.88 GiB
Free  PE / Size       1442 / 5.63 GiB
VG UUID               ASX7Lb-Y0p6-YCGH-hNYp-ewdK-iFse-fq7uWw

[root@CentOS ~]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root   50G   11G   37G  22% /
tmpfs                          3.9G   72K  3.9G   1% /dev/shm
/dev/sda1                      485M   40M  421M   9% /boot
/dev/mapper/vg_centos-lv_home   40G  178M   38G   1% /home
[root@CentOS ~]#
[root@CentOS ~]#
[root@CentOS ~]# resize2fs -p /dev/mapper/vg_centos-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_centos-lv_root is mounted on /; on-line resizing required
old desc_blocks = 4, new_desc_blocks = 29
Performing an on-line resize of /dev/mapper/vg_centos-lv_root to 117964800 (4k) blocks.
The filesystem on /dev/mapper/vg_centos-lv_root is now 117964800 blocks long.

[root@CentOS ~]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos-lv_root  443G   11G  411G   3% /
tmpfs                          3.9G   72K  3.9G   1% /dev/shm
/dev/sda1                      485M   40M  421M   9% /boot
/dev/mapper/vg_centos-lv_home   40G  178M   38G   1% /home