在esx server上安装虚拟机时，由于只分配了默认的8GB磁盘空间。空间不太够，所以在虚拟机上把分配磁盘空间扩大的20GB。在esx server上扩容磁盘空间的方法很简单，在此不提，下面具体说说如何把该扩容的磁盘空间在虚拟机上应用上去。
以下是未扩容前的状态：
- [root@localhost ~]# fdisk -l
- Disk /dev/sda: 21.4 GB, 21474836480 bytes
- 255 heads, 63 sectors/track, 2610 cylinders
- Units = cylinders of 16065 * 512 = 8225280 bytes
- Device Boot Start End Blocks Id System
- /dev/sda1 * 1 13 104391 83 Linux
- /dev/sda2 14 1044 8281507+ 8e Linux LVM
- [root@localhost ~]# df -h
- Filesystem Size Used Avail Use% Mounted on
- /dev/mapper/VolGroup-LogVol00
- 7.0G 4.8G 1.8G 73% /
- /dev/sda1 99M 12M 82M 13% /boot
- tmpfs 187M 0 187M 0% /dev/shm
- /dev/hdc 183M 183M 0 100% /media/VMware Tools
可以看到sda有21.4GB，但是只利用了sda1和sda2；根目录挂载在/dev/mapper/VolGroup-LogVol00，我们要做的是，把sda上剩余的空间扩容到/dev/mapper/VolGroup-LogVol00。
1）首先，通过fdisk /dev/sda命令将sda剩余空间创建一个分区：
- [root@localhost ~]# fdisk /dev/sda
- The number of cylinders for this disk is set to 2610.
- There is nothing wrong with that, but this is larger than 1024,
- and could in certain setups cause problems with:
- 1) software that runs at boot time (e.g., old versions of LILO)
- 2) booting and partitioning software from other OSs
- (e.g., DOS FDISK, OS/2 FDISK)
- Command (m for help): m
- Command action
- a toggle a bootable flag
- b edit bsd disklabel
- c toggle the dos compatibility flag
- d delete a partition
- l list known partition types
- m print this menu
- n add a new partition
- o create a new empty DOS partition table
- p print the partition table
- q quit without saving changes
- s create a new empty Sun disklabel
- t change a partition's system id
- u change display/entry units
- v verify the partition table
- w write table to disk and exit
- x extra functionality (experts only)
- Command (m for help): n
- Command action
- e extended
- p primary partition (1-4)
- p
- Partition number (1-4): 3
- First cylinder (1045-2610, default 1045):
- Using default value 1045
- Last cylinder or +size or +sizeM or +sizeK (1045-2610, default 2610):
- Using default value 2610
- Command (m for help): w
- The partition table has been altered!
- Calling ioctl() to re-read partition table.
- WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
- The kernel still uses the old table.
- The new table will be used at the next reboot.
- Syncing disks.
- [root@localhost ~]#
此时可以看到多了一个sda3的分区：
- [root@localhost ~]# fdisk -l
- Disk /dev/sda: 21.4 GB, 21474836480 bytes
- 255 heads, 63 sectors/track, 2610 cylinders
- Units = cylinders of 16065 * 512 = 8225280 bytes
- Device Boot Start End Blocks Id System
- /dev/sda1 * 1 13 104391 83 Linux
- /dev/sda2 14 1044 8281507+ 8e Linux LVM
- /dev/sda3 1045 2610 12578895 83 Linux
此时查看了一下/dev下，不知道为何没有/dev/sda3，于是重启了一下虚拟机RHEL，重启完成后，出现了/dev/sda3.
一开始在这个地方折腾了一会，如果不重启，在利用命令pvcreate /dev/sda3创建pv时，总是提示Device /dev/sda3 not found (or ignored by filtering).
重启完成后，进入lvm模式，创建pv：
- lvm> pvcreate /dev/sda3
- Physical volume "/dev/sda3" successfully created
扩容vg：vgextend vg_gcc /dev/sda3
- lvm> vgextend VolGroup /dev/sda3
- /dev/cdrom: open failed: Read-only file system
- Attempt to close device '/dev/cdrom' which is not open.
- Volume group "VolGroup" successfully extended
把lv扩容到vg的剩余容量：lvextend /dev/vg_gcc/lv_root /dev/sda3
- lvm> lvextend /dev/VolGroup/LogVol00 /dev/sda3
- Extending logical volume LogVol01 to 12.72 GB
- Logical volume LogVol01 successfully resized
***，通过resize2fs命令令新增的空间在线（on-line）生效：resize2fs /dev/vg_gcc/lv_root
- [root@localhost dev]# resize2fs /dev/VolGroup/LogVol00
- resize2fs 1.39 (29-May-2006)
- Filesystem at /dev/VolGroup/LogVol00 is mounted on /; on-line resizing required
- Performing an on-line resize of /dev/VolGroup/LogVol00 to 5005312 (4k) blocks.
- The filesystem on /dev/VolGroup/LogVol00 is now 5005312 blocks long.
效果如下：
- [root@localhost dev]# df -h
- Filesystem Size Used Avail Use% Mounted on
- /dev/mapper/VolGroup-LogVol00
- 19G 4.8G 13G 28% /
- /dev/sda1 99M 12M 82M 13% /boot
- tmpfs 187M 0 187M 0% /dev/shm
- /dev/hdc 3.4G 3.4G 0 100% /media/RHEL_5.2 x86_64 DVD
至此，扩容已成功完成。
