redhat 5.5 无损 缩小 LVM 空间

由于采用KS安装了系统，不小心把一个挂载点设置的1000G，太大，决定缩小LVM的空间。如下：
[root@localhost ~]# df -lh
文件系统              容量  已用 可用 已用% 挂载点
/dev/mapper/vg_root-lv_www
                     1000G  200M  948G   1% /www
 cd /www
[root@localhost www]# ll
总计 16K
drwx------ 2 root root 16K 2010-07-03 lost+found
#######顺便测试一下缩小时会不会破会数据，简单的一个测试。有数据还是要小心，最好先备份。
[root@localhost www]# mkdir test
[root@localhost www]# vi log.log
dfakfl;aksdflakldfaklfa
[root@localhost /]# umount /www
[root@localhost /]#  e2fsck -f /dev/vg_root/lv_www ###强迫检查文件系统正确性
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/vg_root/lv_www: 13/270499840 files (7.7% non-contiguous), 8521916/270475264 blocks
[root@localhost /]# resize2fs  /dev/vg_root/lv_www 100G ###首先缩小文件系统
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg_root/lv_www to 26214400 (4k) blocks.
The filesystem on /dev/vg_root/lv_www is now 26214400 blocks long.
[root@localhost /]# lvresize -L 100G /dev/vg_root/lv_www  ####其次缩小lv 大小
  WARNING: Reducing active logical volume to 100.00 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv_www? [y/n]: y
  Reducing logical volume lv_www to 100.00 GB
  Logical volume lv_www successfully resized
[root@localhost /]#  mount -a
[root@localhost /]# df -lh
文件系统              容量  已用 可用 已用% 挂载点
/dev/mapper/vg_root-lv_www
                       97G  188M   93G   1% /www
[root@localhost /]# cd /www
[root@localhost www]# ll
总计 32K
-rw-r--r-- 1 root root   24 07-03 14:14 log.log
drwx------ 2 root root  16K 2010-07-03 lost+found
drwxr-xr-x 2 root root 4.0K 07-03 14:14 test
[root@localhost www]# cat log.log
dfakfl;aksdflakldfaklfa
数据没有被破会。
pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda3
  VG Name               vg_root
  PV Size               1.09 TB / not usable 25.21 MB
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              35577
  Free PE               29817 ###多出来的
  Allocated PE          5760
  PV UUID               Wtf68r-1aMo-If26-IlfD-1HB9-eaq8-6yj2Mb
vgdisplay
  --- Volume group ---
  VG Name               vg_root
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  7
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                5
  Open LV               5
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1.09 TB
  PE Size               32.00 MB
  Total PE              35577
  Alloc PE / Size       5760 / 180.00 GB
  Free  PE / Size       29817 / 931.78 GB  ##同样VG也是多出来了
  VG UUID               MoTja0-figK-HMSR-7566-FR2f-00kq-UL6CQx