一.操作过程

1.df -h 查看分区大小情况;

[root@localhost /]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

50G  1.9G   45G   5% /

tmpfs                 7.5G     0  7.5G   0% /dev/shm

/dev/sda1             477M   90M  362M  20% /boot

/dev/mapper/VolGroup-lv_home

860G  101M  816G   1% /home

tmpfs                 4.0G     0  4.0G   0% /var/spool/MailScanner/incoming

2.卸载home分区

[root@localhost /]# umount /home

3.查看卸载情况

[root@localhost /]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

50G  1.9G   45G   5% /

tmpfs                 7.5G     0  7.5G   0% /dev/shm

/dev/sda1             477M   90M  362M  20% /boot

tmpfs                 4.0G     0  4.0G   0% /var/spool/MailScanner/incoming

4.重新整合home分区

[root@localhost /]# e2fsck -f /dev/mapper/VolGroup-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/VolGroup-lv_home: 50/57212928 files (10.0% non-contiguous), 3649291/228843520 blocks

5.从新设定home分区的大小：

[root@localhost /]# resize2fs -p /dev/mapper/VolGroup-lv_home 50G

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/mapper/VolGroup-lv_home to 13107200 (4k) blocks.

Begin pass 2 (max = 32849)

Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Begin pass 3 (max = 6984)

Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Begin pass 4 (max = 17)

Updating inode references     XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

The filesystem on /dev/mapper/VolGroup-lv_home is now 13107200 blocks long.

6.重新挂载home分区

[root@localhost /]# mount /home

7.查看挂载情况

[root@localhost /]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

50G  1.9G   45G   5% /

tmpfs                 7.5G     0  7.5G   0% /dev/shm

/dev/sda1             477M   90M  362M  20% /boot

tmpfs                 4.0G     0  4.0G   0% /var/spool/MailScanner/incoming

/dev/mapper/VolGroup-lv_home

50G   81M   47G   1% /home

7.将lv_home逻辑分区减小到指定大小

[root@localhost /]# lvreduce -L 50 /dev/mapper/VolGroup-lv_home

Rounding size to boundary between physical extents: 52.00 MiB.

WARNING: Reducing active and open logical volume to 52.00 MiB.

THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce VolGroup/lv_home? [y/n]: y

Size of logical volume VolGroup/lv_home changed from 872.97 GiB (223480 extents) to 52.00 MiB (13 extents).

Logical volume lv_home successfully resized.

8.查询卷组的信息：

[root@localhost /]# vgdisplay

--- Volume group ---

VG Name               VolGroup

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               930.51 GiB

PE Size               4.00 MiB

Total PE              238210

Alloc PE / Size       14743 / 57.59 GiB

Free  PE / Size       223467 / 872.92 GiB           #Free PE / Size指定的应该是现在可在分配的空间

VG UUID               Acapyj-Dw5o-Hi3c-RLVe-AmHl-AD83-Nek4Qv

9.增加root分区的大小

Size of logical volume VolGroup/lv_root changed from 50.00 GiB (12800 extents) to 922.00 GiB (236032 extents).

Logical volume lv_root successfully resized.

10.从新设定root分区的大小：

[root@localhost /]# resize2fs -p /dev/mapper/VolGroup-lv_root

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/mapper/VolGroup-lv_root is mounted on /; on-line resizing required

old desc_blocks = 4, new_desc_blocks = 58

Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 241696768 (4k) blocks.

The filesystem on /dev/mapper/VolGroup-lv_root is now 241696768 blocks long.

11.重新查看分区大小

[root@localhost /]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

908G  1.9G  860G   1% /

tmpfs                 7.5G     0  7.5G   0% /dev/shm

/dev/sda1             477M   90M  362M  20% /boot

tmpfs                 4.0G     0  4.0G   0% /var/spool/MailScanner/incoming

/dev/mapper/VolGroup-lv_home

50G   81M   47G   1% /home

二.遇到问题解决办法

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：

[plain] view plaincopyprint?

[root@CentOS-78 /]# fuser -m /home

[root@CentOS-78 /]#

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。