增加硬盘比较好操作，关机，调整硬盘大小即可。
但减小，真的麻烦，我觉得比较靠谱的是以下这种方法。
尽管我在大硬盘上太费时间：
http://norsysadmin.wordpress.com/2013/03/05/shrinking-a-thick-provisioned-disk-in-vmware-esxi-5-1/
Shrinking a thick provisioned disk in VMWare ESXI 5.1
Being new to virtualization, I made the mistake of making the provisioned disk on my Windows 2008 template about 100 GB too large, resulting in our SAN being filled up too fast. Thinking that virtual machines were magical, and hardware could be configured as I wanted, I thought shrinking the disk should be easy. But it wasn’t. After going through a lot of guides, none that worked, I found this method to work:
Short version:
- Shrink disks in windows
- Do a V2V-conversion in VMware converter, with reconfig of the disk.
Longer version:
- Shrink the disk(s)/remove unused disks in the disk management tool in windows (a mmc snap-in in Windows S2008)
- Install VMware vCenter converter 5.0.1 (earlier versions like 5.0.0 isn’t compatible with ESXI 5.1)
- Choose “Convert machine”
- Connect to your vCenter administration machine as source
- Choose the machine you want to shrink the disk on.
- Connect to your vCenter administration machine as destination.
- Edit the disk-size (include only the drives you need) under options.
- Wait while copying
- Remove the old virtual machine (the source with too large disk)
- Profit!