如果需要將一個已經掛載的分區進行容量縮小，將騰出的容量劃分成其他分區，需要怎麼做呢？下面爲詳細步驟：
1.卸載
touch /opt/test.txt -->寫入一些文件
umount /opt
2.文件系統檢查
fsck -f /dev/mapper/VolGroup00-LogVol00_opt
fsck 1.39 (29-May-2006)
e2fsck 1.39 (29-May-2006)
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/VolGroup00-LogVol00_opt: 41641/135479296 files (0.7% non-contiguous), 31756336/270958592 blocks
3.調整文件系統的大小
resize2fs /dev/mapper/VolGroup00-LogVol00_opt 500G
–>將VolGroup00-LogVol00_opt瘦小到500G
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/mapper/VolGroup00-LogVol00_opt to 131072000 (4k) blocks.
The filesystem on /dev/mapper/VolGroup00-LogVol00_opt is now 131072000 blocks long.
4.裁減邏輯卷
lvreduce -L 500G /dev/mapper/VolGroup00-LogVol00_opt
WARNING: Reducing active logical volume to 500.00 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LogVol00_opt? [y/n]: y
Reducing logical volume LogVol00_opt to 500.00 GB
Logical volume LogVol00_opt successfully resized
5.再次檢查文件系統是否出現錯誤
fsck -f /dev/mapper/VolGroup00-LogVol00_opt
fsck 1.39 (29-May-2006)
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Chaaaaecking group summary information
/dev/mapper/VolGroup00-LogVol00_opt: 41641/65536000 files (0.7% non-contiguous), 29561045/131072000 blocks
6.掛載
mount -t ext3 /dev/mapper/VolGroup00-LogVol00_opt /opt
df -h
/dev/mapper/VolGroup00-LogVol00_orabak 493G 198M 467G 1% /orabak
增加lvm：
lvextend -n /dev/mapper/VolGroup00-orabak -L +100G
resize2fs /dev/mapper/VolGroup00-orabak