First of all, deleting snapshots takes seconds or a couple of minutes in Hyper-V. If you don’t, you can run into some serious problems. It is meant to be used for 24-28 hours after which you should delete them. Unlike Hyper-V snapshots which can be actually useful in the long term because you can keep a bunch of snapshots indefinitely and go back and forth between them without any problem, VMware is not designed to use snapshot for similar purposes. Frankly, they are much more complicated and are meant to be used only temporarily. VMware snapshots are very different than Hyper-V snapshots. If in step 6 you are unable to increase the size of the disk because the provisioning option is grayed out, you need to make sure that you delete all the existing snapshots. Your drive size will increase right away and there is no need to reboot the computer.It should take only a few seconds to run through the wizard. Right-click drive C and select Extend Volume.You will notice unallocated space at the end of the disks.
In Windows Server 2008 R2 go to Server Manager, Storage, Disk Management.
You must power off the VM and then delete the snapshots before you can expand the disks. You select Edit Settings and select the hard disk that is running out of disk space but the option to expand the disk is grayed out. You go to the vSphere Client utility and select the VM. Over the last few months you have taken a dozen snapshots. After a few months you realize that you have installed a lot of programs and your VM hard disk is running out of space. Your ESXi server’s hard disk is 1TB in size and you have a VM running a Windows Server 2008 R2 guest operating system that has two drives, a 30GB drive C and a 20GB drive D.
Let’s use the following scenario as an example. Keep in mind that increasing the size of the VM is different than increasing the size of the disk partition on the host computer.
But if you have any snapshots, it can be a pain. If you are running VMware ESXi 4.1 you can increase the size of the virtual machine (VM) relatively easily once you know how.