**因為開始裝的服務器用的自動lvm，后來發現home下分區太大了，/分區太小。zabbix報警空間已用80%，所以必須要壓縮home分區給/目錄 **
感覺亂亂的，整理一下使用的命令按順序和思路，能完成的后面就不用看了：
1.umount /home ###如果發現busy不能卸載就fuser -m /home查看一下是什么進程在占用，然后kill -9 殺掉
2.resize2fs -p /dev/mapper/VolGroup-lv_home 20G ###先設置一下home的大小，做這部的時候會提醒讓先運行下面的命令進行檢查
3.e2fsck -f /dev/mapper/VolGroup-lv_home ###強制檢查一下磁盤並修復錯誤
4.resize2fs -p /dev/mapper/VolGroup-lv_home 20G ###再次運行這個命令把home大小設置為20G
5.lvreduce -L 20G /dev/mapper/VolGroup-lv_home ###收縮邏輯卷空間為20G
6.mount /home ###並du -f 查看一下home 大小分配是否成功
7.lvextend -l +100%FREE /dev/mapper/VolGroup-lv_root ###把剩余的所有空間都分配給/目錄
8.resize2fs -p /dev/mapper/VolGroup-lv_root ###執行調整根目錄的空間大小，並耐心等待，不要操作
9.#等待一段時間后就成功了 df -h看看吧
- 首先：以防萬一先備份好/home下的文件，然后umount /home分區
如果發現umount /home分區的時候提示busy說明有進程在占用home分區
建議用fuser -m /home命令進行查看一下,然后kill -9 殺掉進程。 - 然后，
umount /home
[root@localhost ~]# umount /home
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 40G 7.4G 85% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
[root@localhost ~]# resize2fs -p /dev/mapper/
control VolGroup-lv_home VolGroup-lv_root VolGroup-lv_swap
[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_home 20G
resize2fs 1.41.12 (17-May-2010)
請先運行 'e2fsck -f /dev/mapper/VolGroup-lv_home'.
[root@localhost ~]# e2fsck -f /dev/mapper/VolGroup-lv_home
e2fsck 1.41.12 (17-May-2010)
第一步: 檢查inode,塊,和大小
第二步: 檢查目錄結構
第3步: 檢查目錄連接性
Pass 4: Checking reference counts
第5步: 檢查簇概要信息
/dev/mapper/VolGroup-lv_home: 124/13942784 files (8.1% non-contiguous), 966453/55744512 blocks
[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_home 20G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/VolGroup-lv_home to 5242880 (4k) blocks.
Begin pass 2 (max = 32873)
正在重定位塊 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 1702)
正在掃描inode表 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 22)
正在更新inode引用 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/mapper/VolGroup-lv_home is now 5242880 blocks long.
[root@localhost ~]# mount /home
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 50G 40G 7.4G 85% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 20G 342M 19G 2% /home
這樣就成功把/home分區成功調整到20G大小了，接下來我們進行操作，把剩下的空間分給根目錄
[root@localhost ~]# lvextend -l +100%FREE /dev/mapper/VolGroup-lv_rootlvreduce -L 20G /dev/mapper/VolGroup-lv_home
WARNING: Reducing active and open logical volume to 20.00 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 20.00 GiB
Logical volume lv_home successfully resized
[root@localhost ~]# lvextend -l +100%FREE /dev/mapper/VolGroup-lv_root
Extending logical volume lv_root to 242.65 GiB
Logical volume lv_root successfully resized
[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 = 16
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 63608832 (4k) blocks.
然后就是漫長的等待
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 114G 40G 69G 37% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 20G 342M 19G 2% /home
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 117G 40G 71G 36% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 20G 342M 19G 2% /home
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root 118G 40G 73G 36% /
tmpfs 16G 0 16G 0% /dev/shm
/dev/sda1 485M 39M 421M 9% /boot
/dev/mapper/VolGroup-lv_home 20G 342M 19G 2% /home
可以看到正在擴容，完事