管理LVM2逻辑分区

命令格式：
resize2fs device size
lvreduce -L size lv名或者路径
和增大分区相似，resize2fs命令在最后加上新容量大小；lvreduce命令如果要跟减量的话，就变成了“-”。

我的命令：
卸载文件系统
# df -B m
文件系统               1M-块        已用     可用 已用% 挂载点
/dev/mapper/DeYang-root
                          268M      116M      139M  46% /
tmpfs                     379M        0M      379M   0% /lib/init/rw
udev                       10M        1M       10M   1% /dev
tmpfs                     379M        1M      379M   1% /dev/shm
/dev/hda1                 236M       19M      206M   9% /boot
/dev/mapper/DeYang-tmp
                          380M       11M      350M   3% /tmp
/dev/mapper/DeYang-usr
                         5832M     3786M     1756M  69% /usr
/dev/mapper/DeYang-var
                         2886M      561M     2180M  21% /var
/dev/mapper/DeYang-home
                        55121M     8831M    43490M  17% /home
/dev/mapper/DeYang-testlv
                         1008M        2M      956M   1% /mnt/tmp
# umount /dev/DeYang/testlv
#
# resize2fs /dev/DeYang/testlv 800M
resize2fs 1.40-WIP (14-Nov-2006)
Please run 'e2fsck -f /dev/DeYang/testlv' first.

# e2fsck -f /dev/DeYang/testlv
e2fsck 1.40-WIP (14-Nov-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/DeYang/testlv: 11/131072 files (9.1% non-contiguous), 4443/262144 blocks
#
# resize2fs /dev/DeYang/testlv 800M
resize2fs 1.40-WIP (14-Nov-2006)
Resizing the filesystem on /dev/DeYang/testlv to 204800 (4k) blocks.
The filesystem on /dev/DeYang/testlv is now 204800 blocks long.

#
# lvreduce -L 800M /dev/DeYang/testlv
  WARNING: Reducing active logical volume to 800.00 MB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce testlv? [y/n]: y
  Reducing logical volume testlv to 800.00 MB
  Logical volume testlv successfully resized
#
# mount /dev/DeYang/testlv /mnt/tmp/
# df -B m
文件系统               1M-块        已用     可用 已用% 挂载点
/dev/mapper/DeYang-root
                          268M      116M      139M  46% /
tmpfs                     379M        0M      379M   0% /lib/init/rw
udev                       10M        1M       10M   1% /dev
tmpfs                     379M        1M      379M   1% /dev/shm
/dev/hda1                 236M       19M      206M   9% /boot
/dev/mapper/DeYang-tmp
                          380M       11M      350M   3% /tmp
/dev/mapper/DeYang-usr
                         5832M     3786M     1756M  69% /usr
/dev/mapper/DeYang-var
                         2886M      561M     2180M  21% /var
/dev/mapper/DeYang-home
                        55121M     8831M    43490M  17% /home
/dev/mapper/DeYang-testlv
                          786M        2M      753M   1% /mnt/tmp
#


参考资料：
1、LVM HOWTO，http://www.tldp.org/HOWTO/LVM−HOWTO.html；