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 % /
tmpfs .8G 160K .8G % /dev/shm
/dev/sda1 485M 40M 420M % /boot
/dev/mapper/vg_slave6-lv_home 860G 25G 792G % /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() or fuser())
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. (-May-)
Pass : Checking inodes, blocks, and sizes
Pass : Checking directory structure
Pass : Checking directory connectivity
Pass : Checking reference counts
Pass : Checking group summary information
/dev/mapper/vg_slave6-lv_home: / files (1.2% non-contiguous), / blocks
设置home的大小为200G
[root@Slave1 /]# resize2fs -p /dev/mapper/vg_slave6-lv_home 200G
resize2fs 1.41. (-May-)
Resizing the filesystem on /dev/mapper/vg_slave6-lv_home to (4k) blocks.
Begin pass (max = )
Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass (max = )
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass (max = )
Updating inode references XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/vg_slave6-lv_home is now 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 % /
tmpfs .8G 232K .8G % /dev/shm
/dev/sda1 485M 40M 420M % /boot
/dev/mapper/vg_slave6-lv_home 197G 25G 163G % /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
Metadata Sequence No
VG Access read/write
VG Status resizable
MAX LV
Cur LV
Open LV
Max PV
Cur PV
Act PV
VG Size 931.02 GiB
PE Size 4.00 MiB
Total PE
Alloc PE / Size / 257.79 GiB
Free PE / Size / 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 +.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 +.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. (-May-)
Filesystem at /dev/mapper/vg_slave6-lv_root is mounted on /; on-line resizing required
old desc_blocks = , new_desc_blocks =
Performing an on-line resize of /dev/mapper/vg_slave6-lv_root to (4k) blocks.
The filesystem on /dev/mapper/vg_slave6-lv_root is now 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 % /
tmpfs .8G 232K .8G % /dev/shm
/dev/sda1 485M 40M 420M % /boot
/dev/mapper/vg_slave6-lv_home 197G 25G 163G % /home
大功告成，home，root中的内容没有丢失