/dev/sdc，只有一个sdc1分区，
[root@centos68 /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_centos68-lv_root
63G 20G 40G 34% /
tmpfs 2.0G 0 2.0G 0% /dev/shm
/dev/sda1 477M 40M 412M 9% /boot
/dev/sr0 3.7G 3.7G 0 100% /mnt
glusterfs1:da_gfs_1 28T 1.2G 28T 1% /opt/gfs_test
/dev/sdc1 16G 144M 15G 1% /data
在vcenter中将虚拟机的硬盘修改为20G
echo 1 > /sys/class/scsi_disk/2\:0\:2\:0/device/rescan 重扫磁盘
fdisk识别为20G
扩展流程：卸载分区、删除分区表、重建分区表、resize2fs sdc1、挂载sdc1，扩容成功，如下：
[root@centos68 ~]# fdisk /dev/sdc
WARNING: DOS-compatible mode is deprecated. It’s strongly recommended to
switch off the mode (command ‘c’) and change display units to
sectors (command ‘u’).
Command (m for help): p
Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb32885bf
Device Boot Start End Blocks Id System
/dev/sdc1 1 2088 16771828+ 83 Linux
Command (m for help): d
Selected partition 1
Command (m for help): p
Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb32885bf
Device Boot Start End Blocks Id System
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610):
Using default value 2610
Command (m for help): p
Disk /dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb32885bf
Device Boot Start End Blocks Id System
/dev/sdc1 1 2610 20964793+ 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@centos68 ~]# resize2fs /dev/sdc
sdc sdc1
[root@centos68 ~]# resize2fs /dev/sdc1
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/sdc1 to 5241198 (4k) blocks.
The filesystem on /dev/sdc1 is now 5241198 blocks long.
容量已更新：
[root@centos68 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_centos68-lv_root
63G 20G 40G 34% /
tmpfs 2.0G 0 2.0G 0% /dev/shm
/dev/sda1 477M 40M 412M 9% /boot
/dev/sr0 3.7G 3.7G 0 100% /mnt
glusterfs1:da_gfs_1 28T 1.2G 28T 1% /opt/gfs_test
/dev/sdc1 20G 145M 19G 1% /data
