之前曾经发过教程：
- 1: 如何扩容LV磁盘分区 (0)
- 2: 如何调整LV磁盘分区大小 (0)
- 3: linux下创建LV逻辑卷并挂载磁盘过程 (1)
今天发现http://blog.csdn.net/a921122/article/details/51955764这里一个教程比较适合我今天机器具体情况。
机器分区具体信息：
[root@mx-42 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 1.9G 45G 5% /
tmpfs 32G 0 32G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 389G 199M 369G 1% /home
客户一再强调，所有分区都给/，也就是磁盘挂载到/下，但是机房装机人员，有时候会按照他自己的想法和习惯，给客户提供机器。没办法，老易拿到机器后，还要根据客户具体要求，对磁盘分区做出调整。目标就是把/的50G空间，搞到最大。一看/home下有369G空间可用，那就总体思路是减小/home的空间，然后把这部分空间扩展到/去。
[root@mx-42 /]# pvdisplay
— Physical volume —
PV Name /dev/sda2
VG Name VolGroup
PV Size 476.45 GiB / not usable 0
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 121971
Free PE 0
Allocated PE 121971
PV UUID FPGB3H-LS5O-Jhh2-66Jp-G1FC-C6QJ-CTqnCk
[root@mx-42 /]# vgdisplay
— Volume group —
VG Name VolGroup
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
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 476.45 GiB
PE Size 4.00 MiB
Total PE 121971
Alloc PE / Size 121971 / 476.45 GiB
Free PE / Size 0 / 0
VG UUID guDukn-EeCl-JMxR-usgg-4HTb-Kqp6-ppZGCA
以下是照葫芦画瓢，操作过程：
umount /home，先卸载/home，然后把/home变成1G
[root@mx-42 /]# resize2fs -p /dev/mapper/VolGroup-lv_home 1G
resize2fs 1.41.12 (17-May-2010)
Please run ‘e2fsck -f /dev/mapper/VolGroup-lv_home’ first.
提示：先进行磁盘检查。
[root@mx-42 /]# 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: 11/25886720 files (0.0% non-contiguous), 1675464/103529472 blocks
重新规划/home大小是1G：
[root@mx-42 /]# resize2fs -p /dev/mapper/VolGroup-lv_home 1G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/VolGroup-lv_home to 262144 (4k) blocks.
Begin pass 2 (max = 32768)
Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 3160)
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/VolGroup-lv_home is now 262144 blocks long.
[root@mx-42 /]# mount /home/
[root@mx-42 /]# mount -l
/dev/mapper/VolGroup-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext=”system_u:object_r:tmpfs_t:s0″)
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
/dev/mapper/VolGroup-lv_home on /home type ext4 (rw)
[root@mx-42 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 1.9G 45G 5% /
tmpfs 32G 0 32G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 1008M 149M 809M 16% /home
释放/home空间：
[root@mx-42 /]# lvreduce -L 1G /dev/mapper/VolGroup-lv_home
WARNING: Reducing active and open logical volume to 1.00 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 1.00 GiB
Logical volume lv_home successfully resized
[root@mx-42 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 1.9G 45G 5% /
tmpfs 32G 0 32G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 1008M 149M 809M 16% /home
[root@mx-42 /]# vgdisplay
— Volume group —
VG Name VolGroup
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 476.45 GiB
PE Size 4.00 MiB
Total PE 121971
Alloc PE / Size 21124 / 82.52 GiB
Free PE / Size 100847 / 393.93 GiB
VG UUID guDukn-EeCl-JMxR-usgg-4HTb-Kqp6-ppZGCA
空闲空间加入到lv_root：
[root@mx-42 /]# lvextend -L +393.93G /dev/mapper/VolGroup-lv_root
Rounding size to boundary between physical extents: 393.93 GiB
Extending logical volume lv_root to 443.93 GiB
Logical volume lv_root successfully resized
最后一步要耐心等待，扩大越多，时间越长 ：
[root@mx-42 /]# 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 = 28
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 116374528 (4k) blocks.
The filesystem on /dev/mapper/VolGroup-lv_root is now 116374528 blocks long.
[root@mx-42 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 437G 2.0G 413G 1% /
tmpfs 32G 0 32G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 1008M 149M 809M 16% /home