通过命令给Linux(CentOS)分区
服务器供应商给了linux服务器后，发现放root与数据的分区太小，只有150G左右，而/home却高达300G，?空间利用率很是问题。于是，想办法重新分区。但是，Linux重新分区很麻烦，不过，只要按照下列步骤做，一般就没有什么问题。
但是，请注意，如果你的系统现在在运行中，已经有不少数据，建议你先备份，以防万一。再者，你需要调整的分区一定不能大于原有文件所占有的空间，否则，一定造成数据丢失！！！
下面的例子你可以看出，我们原来默认的分区不合理，/root仅有150G左右，而/home则有大约300G：
首先，你可以通过以下指令查看你分区的现状：
[root@localhost ~]# df –h(查看分区状况)
文件系统??????????容量??已用??可用?已用%%?挂载点
/dev/mapper/VolGroup-lv_root
??????????????????????154G??7.9G??139G???6% /
tmpfs?????????????????1.9G??100K??1.9G???1% /dev/shm
/dev/sda1?????????????485M???69M??391M??15% /boot
/dev/mapper/VolGroup-lv_home
??????????????????????299G??984M??283G???1% /home
因为我们想缩小/home，先卸载/home：
[root@localhost ~]# umount /home（卸载/home）
[root@localhost ~]#?e2fsck -f /dev/mapper/VolGroup-lv_home(检查VolGroup-lv_home文件的错误性，-f???即使文件系统没有错误迹象，仍强制地检查正确性。)
e2fsck 1.41.12 (17-May-2010)
第一步:?检查inode,块,和大小
第二步:?检查目录结构
第3步:?检查目录连接性
Pass 4: Checking reference counts
第5步:?检查簇概要信息
/dev/mapper/VolGroup-lv_home: 21/19857408 files (0.0% non-contiguous), 1498180/79429632 blocks
因为/home仅仅装了系统，所以不需要太多空间，我们决定调整到很小：
[root@localhost ~]# resize2fs -p /dev/mapper/VolGroup-lv_home 20G（调整mapper/VolGroup-lv_home文件大小为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 = 32778)
正在重定位块????????????XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 2424)
正在扫描inode表??????????XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 10)
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（挂在?/home）
[root@localhost ~]# df –h (查看分区状况)
文件系统??????????容量??已用??可用?已用%%?挂载点
/dev/mapper/VolGroup-lv_root
??????????????????????154G??7.9G??139G???6% /
tmpfs?????????????????1.9G??100K??1.9G???1% /dev/shm
/dev/sda1?????????????485M???69M??391M??15% /boot
/dev/mapper/VolGroup-lv_home
???????????????????????20G??962M???18G???6% /home
[root@localhost ~]#?lvreduce -L 20G /dev/mapper/VolGroup-lv_home?(lvreduce指令用于减少LVM逻辑卷占用的空间大小。可能会删除逻辑卷上已有的数据，所以在操作前必须进行确认。)
??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 ~]# df –h?(查看分区状况)
文件系统??????????容量??已用??可用?已用%%?挂载点
/dev/mapper/VolGroup-lv_root
??????????????????????154G??7.9G??139G???6% /
tmpfs?????????????????1.9G??100K??1.9G???1% /dev/shm
/dev/sda1?????????????485M???69M??391M??15% /boot
/dev/mapper/VolGroup-lv_home
???????????????????????20G??962M???18G???6% /home
[root@localhost ~]# vgdisplay
??--- Volume group ---
??VG Name???????????????VolGroup
??System ID?????????????
??Format????????????????lvm2
??Metadata Areas????????1
??Metadata Sequence No??7
??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???????????????465.27 GiB
??PE Size???????????????4.00 MiB
??Total PE??????????????119109
??Alloc PE / Size???????46660 / 182.27 GiB
??Free??PE / Size???????72449 / 283.00 GiB
??VG UUID???????????????gPA8XS-ZncK-mGQj-2Vn9-TFTQ-6yOU-6atjE9
???
[root@localhost ~]# lvextend -L +283G /dev/mapper/VolGroup-lv_root?(lvextend指令：扩展逻辑卷空间)
??Extending logical volume lv_root to 439.39 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 = 10, new_desc_blocks = 28
Performing an on-line resize of /dev/mapper/VolGroup-lv_root to 115183616 (4k) blocks.
The filesystem on /dev/mapper/VolGroup-lv_root is now 115183616 blocks long.
?
现在检查一下调整的结果：
[root@localhost ~]# df -h
文件系统??????????容量??已用??可用?已用%%?挂载点
/dev/mapper/VolGroup-lv_root
??????????????????????433G??7.9G??403G???2% /
tmpfs?????????????????1.9G??100K??1.9G???1% /dev/shm
/dev/sda1?????????????485M???69M??391M??15% /boot
/dev/mapper/VolGroup-lv_home
???????????????????????20G??962M???18G???6% /home
[root@localhost ~]#
做起来很顺利，节省了重装的时间。
