0、看有没有lvs
#lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv_home vg_vhost -wi-ao---- 5.40t
lv_root vg_vhost -wi-ao---- 50.00g
lv_swap vg_vhost -wi-ao---- 7.80g
1、先来查看一下系统的空间分配情况
#df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_vhost-lv_root
50G 40G 7.0G 86% /
tmpfs 7.8G 0 7.8G 0% /dev/shm
/dev/sda1 477M 28M 425M 7% /boot
/dev/mapper/vg_vhost-lv_home
5.4T 15G 5.1T 1% /home
2、目标-》增加 /空间，减少 /home空间，缩减vg_vhost-lv_home到2T
#resize2fs -p /dev/mapper/vg_vhost-lv_home 2T
Filesystem at /dev/mapper/vg_vhost-lv_home is mounted on /home; on-line resizing required
On-line shrinking from 1449448448 to 536870912 not supported.
提示，在线不中
3、卸载目录
#umount /home
4、缩减到2T
#resize2fs -p /dev/mapper/vg_vhost-lv_home 2T
resize2fs 1.41.12 (17-May-2010)
请先运行 ‘e2fsck -f /dev/mapper/vg_vhost-lv_home‘.
5、提示先检查
#e2fsck -f /dev/mapper/vg_vhost-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_vhost-lv_home: 21/362364928 files (4.8% non-contiguous), 26516105/1449448448 blocks
6、缩减
#resize2fs -p /dev/mapper/vg_vhost-lv_home 2T
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/vg_vhost-lv_home to 536870912 (4k) blocks.
Begin pass 2 (max = 32768)
正在重定位块 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 44234)
正在扫描inode表 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/vg_vhost-lv_home is now 536870912 blocks long.
7、重新加载目录
#mount /home
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_vhost-lv_root
50G 40G 7.0G 86% /
tmpfs 7.8G 0 7.8G 0% /dev/shm
/dev/sda1 477M 28M 425M 7% /boot
/dev/mapper/vg_vhost-lv_home
2.0T 15G 1.9T 1% /home
8、使生效，分出空间可用。注意如果有数据，要小于2T，否则丢人
#lvreduce -L 2T /dev/mapper/vg_vhost-lv_home
WARNING: Reducing active and open logical volume to 2.00 TiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg_vhost/lv_home? [y/n]: y
Size of logical volume vg_vhost/lv_home changed from 5.40 TiB (1415477 extents) to 2.00 TiB (524288 extents).
Logical volume lv_home successfully resized.
9、查询卷组的信息：
Free PE / Size指定的应该是现在可在分配的空间
#vgdisplay
--- Volume group ---
VG Name vg_vhost
System ID
Format lvm2
Metadata Areas 2
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 2
Act PV 2
VG Size 5.46 TiB
PE Size 4.00 MiB
Total PE 1430273
Alloc PE / Size 539084 / 2.06 TiB
Free PE / Size 891189 / 3.40 TiB
VG UUID q9cgCG-rlm0-KGYo-Z7xq-6JyO-1hAT-E0ZWpf
10、将可用的空间添加到 /
#lvextend -L +3.4T /dev/mapper/vg_vhost-lv_root
Rounding size to boundary between physical extents: 3.40 TiB.
Insufficient free space: 891290 extents needed, but only 891189 available
#lvextend -L +3.39T /dev/mapper/vg_vhost-lv_root
Rounding size to boundary between physical extents: 3.39 TiB.
Size of logical volume vg_vhost/lv_root changed from 50.00 GiB (12800 extents) to 3.44 TiB (901469 extents).
Logical volume lv_root successfully resized.
11、还是-l后面的参数好用，呵呵
#lvextend -l +100%FREE /dev/mapper/vg_vhost-lv_root
Size of logical volume vg_vhost/lv_root changed from 3.45 TiB (903986 extents) to 3.45 TiB (903989 extents).
Logical volume lv_root successfully resized.
12、查看空间，纳闷啊！！
#df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_vhost-lv_root
50G 40G 7.0G 86% /
tmpfs 7.8G 0 7.8G 0% /dev/shm
/dev/sda1 477M 28M 425M 7% /boot
/dev/mapper/vg_vhost-lv_home
2.0T 15G 1.9T 1% /home
13、使生效，这个过程可慢，在线啊……
#resize2fs -p /dev/mapper/vg_vhost-lv_root
Filesystem at /dev/mapper/vg_vhost-lv_root is mounted on /; on-line resizing required
old desc_blocks = 4, new_desc_blocks = 221
Performing an on-line resize of /dev/mapper/vg_vhost-lv_root to 925684736 (4k) blocks.
The filesystem on /dev/mapper/vg_vhost-lv_root is now 925684736 blocks long.
14、查看空间，ok
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_vhost-lv_root
3.4T 40G 3.2T 2% /
tmpfs 7.8G 0 7.8G 0% /dev/shm
/dev/sda1 477M 28M 425M 7% /boot
/dev/mapper/vg_vhost-lv_home
2.0T 15G 1.9T 1% /home