CentOS根分区扩容方法

操作环境：
[root@linuxidc ~]# uname -a
Linux linuxidc 2.6.32-358.18.1.el6.x86_64#1 SMP Wed Aug 28 17:19:38 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
现状分析：
系统有两个硬盘，第一个硬盘107G,“/”分区空间当时分区时只给了7.7G过小，空间马上占完。现在系统有第二个硬盘sdb大小为16GB，希望把sdb的所有空间加入到“/”分区中，是其空间容量从7.7GB变成7.7GB+16GB（约2.4GB）。（当然如果这里只有一个硬盘sda,有很多空间尚未使用可以进行同样的操作）
操作步骤如下：
第一步、查看本机现有分区情况
[root@linuxidc ~]# df -h
文件系统容量已用可用已用%% 挂载点
/dev/mapper/VolGroup-lv_root
                    7.7G  7.1G 155M  98% /
tmpfs                3.9G  296K 3.9G  1% /dev/shm
/dev/sda1            485M  64M 396M  14% /boot
/dev/sda3              83G  350M  79G  1% /media
第二步、查看本机的磁盘情况
[root@linuxidc ~]# fdisk -l

Disk /dev/sda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000dc0ad

 Device Boot      Start        End      Blocks  Id  System
/dev/sda1  *          1          64      512000  83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        2089  16264192  8e  Linux LVM
/dev/sda3            2090      13054  88076362+  83  Linux

Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000

Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000
注意：此时还没有在EXSI5.0中添加第二块硬盘
[root@linuxidc ~]#
第三步、添加第二块硬盘

查看此时系统磁盘情况
root@linuxidc ~]# fdisk -l

Disk /dev/sda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000dc0ad

 Device Boot      Start        End      Blocks  Id  System
/dev/sda1  *          1          64      512000  83  Linux
Partition 1 does not end on cylinderboundary.
/dev/sda2              64        2089  16264192  8e  Linux LVM
/dev/sda3            2090      13054  88076362+  83  Linux

Disk /dev/sdb: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000

Disk /dev/mapper/VolGroup-lv_root: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000

Disk /dev/mapper/VolGroup-lv_swap: 8325 MB,8325693440 bytes
255 heads, 63 sectors/track, 1012 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000

可以看到我们新添加的硬盘sdb

[root@linuxidc ~]#
第四步、对第二块硬盘sdb进行分区

[root@linuxidc ~]# fdisk /dev/sdb
Device contains neither a valid DOSpartition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with diskidentifier 0xfa4abbdc.
Changes will remain in memory only, untilyou decide to write them.
After that, of course, the previous contentwon't be recoverable.

Warning: invalid flag 0x0000 of partitiontable 4 will be corrected by w(rite)