CentOS无损调整home，root磁盘的大小

调整硬盘分区大小
想增加root空间，减少home空间。

需要说明的是整个操作需要使用root用户。

1.查看硬盘使用情况。

[root@Slave1 /]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_slave6-lv_root   50G   22G   26G  46% /
tmpfs                          7.8G  160K  7.8G   1% /dev/shm
/dev/sda1                      485M   40M  420M   9% /boot
/dev/mapper/vg_slave6-lv_home  860G   25G  792G   4% /home

可以看到home的大小是860G，而root的大小只有50G。

我的目标是将home的大小缩小为200G，其余的加到root中

接下来好戏上演了：

2.卸载/home

[root@Slave1 /]# umount /home
umount: /home: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))

出现这种情况表示有应用程序正在占用home，强制清除掉就可以，使用下边的命令

[root@Slave1 /]# fuser -km /home

强制清除后在进行卸载

[root@Slave1 /]# umount /home

3、调整分区大小

[root@Slave1 /]# e2fsck -f /dev/mapper/vg_slave6-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_slave6-lv_home: 255/57229312 files (1.2% non-contiguous), 10040281/228912128 blocks

设置home的大小为200G

[root@Slave1 /]# resize2fs -p /dev/mapper/vg_slave6-lv_home 200G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/vg_slave6-lv_home to 52428800 (4k) blocks.
Begin pass 2 (max = 32992)
Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 6986)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 123)
Updating inode references     XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/vg_slave6-lv_home is now 52428800 blocks long.

挂载home

[root@Slave1 /]# mount /home
[root@Slave1 /]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_slave6-lv_root   50G   22G   26G  46% /
tmpfs                          7.8G  232K  7.8G   1% /dev/shm
/dev/sda1                      485M   40M  420M   9% /boot
/dev/mapper/vg_slave6-lv_home  197G   25G  163G  14% /home

可以看到home的磁盘大小已经减小到了197G，剩余3G的空间应该是被用掉了

4.释放空间

[root@Slave1 /]# lvreduce -L 200G /dev/mapper/vg_slave6-lv_home
  WARNING: Reducing active and open logical volume to 200.00 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 200.00 GiB
  Logical volume lv_home successfully resized

[root@Slave1 /]# vgdisplay
  --- Volume group ---
  VG Name               vg_slave6
  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       65994 / 257.79 GiB
  Free  PE / Size       172347 / 673.23 GiB
  VG UUID               g1cRWV-O788-QKCc-lQG0-JaEp-s2BB-xNHxF3

会看到有637.23G的剩余空间，接下来要做的就是把这些空间加载到root中

5.增加空余空间到root

[root@Slave1 /]# lvextend -L +673.23G /dev/mapper/vg_slave6-lv_root
  Rounding size to boundary between physical extents: 673.23 GiB
  Extending logical volume lv_root to 723.23 GiB
  Logical volume lv_root successfully resized

接下来这个操作可能需要时间长点，加载的空间越大时间越长。

root@Slave1 /]# lvextend -L +673.23G /dev/mapper/vg_slave6-lv_root
  Rounding size to boundary between physical extents: 673.23 GiB
  Extending logical volume lv_root to 723.23 GiB
  Logical volume lv_root successfully resized
[root@Slave1 /]# resize2fs -p /dev/mapper/vg_slave6-lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_slave6-lv_root is mounted on /; on-line resizing required
old desc_blocks = 4, new_desc_blocks = 46
Performing an on-line resize of /dev/mapper/vg_slave6-lv_root to 189590528 (4k) blocks.
The filesystem on /dev/mapper/vg_slave6-lv_root is now 189590528 blocks long.

查看一下

[root@Slave1 /]# df -h
Filesystem                     Size  Used Avail Use% Mounted on
/dev/mapper/vg_slave6-lv_root  712G   22G  655G   4% /
tmpfs                          7.8G  232K  7.8G   1% /dev/shm
/dev/sda1                      485M   40M  420M   9% /boot
/dev/mapper/vg_slave6-lv_home  197G   25G  163G  14% /home

大功告成，home，root中的内容没有丢失