[ovirt-users] virtual Disk

Hello, i testing oVirt 3.6 as Self-Hosted-Engine and create a virtual machine. Now i want to change the size of the disk and found the possibilities to change the size of the disk and a field to grow the disk. In ovirt manual it is descripted to change the value of the grow field. My question is what is the difference and what are the results of that. E.g what happend if i only change the disk size from 8 to 10? is it the same like i change the grow size from 0 to 2? thx for technical explanation.