Increasing the VMDK size can be done in GUI but decreasing the size of VMDK is not allowed. In most cases, For virtual machine hard disk shrink can be performed via v2v. It is the safest method to reduce the virtual machine VMDK size but there is an another simple approach which saves lot of efforts rather than performing v2v.
we can decreasing the size of VMDK using command by editing the descriptor file for the flat VMDK file and now we can start this steps one by one to be more clarification.
1- open your vCenter server and edit your VM setting and get the name of the vmdk that you want to reduce.
2- the 2nd step we will use putty to connect to the ESXi via ssh.
3- Go to the location of the VM and write command LS to show all VM folder contain.
4-after that write this command cat TEST_1.vmdk this command will appear all the contains of the VMDK descriptor file
5- after that write this command vi TEST_1.vmdk this command can help us to edit the VMDK descriptor file
here i show you the size this number 209715200+100 it’s the size of the VMDK file in this VM and you can calculate it as this way 100*1024*1024*1024=/512
Now we need to edit the size to 50 G write command vi TEST_1.vmdk and press insert to edit file go to RW 209715200 and edit it to
But to reflect this editing you must make Storage vMotion to this virtual machine
or you can delete it from inventory and add it again .
Congratulations, you have successfully Shrunk a VMware Virtual Machine Disk (VMDK)