After you resize a Windows® (VPS, Cloud) Server, you need to perform some additional steps to use the new disk space that is available for your server. In Windows Server® 2012 you can merge the newly available disk space into one drive by expanding your original drive.
Extend your drive
Use the following steps to extend your drive:
1) From the desktop of your Windows Server 2012 Cloud Server, open the Server Manager and select Tools > Computer Management.
2) Under the Storage folder in the left pane, select Disk Management.
The left pane of Disk Management displays the current formatted hard drive for your server, generally C:\, and the right pane displays the amount of unallocated space.
3) Select the C:\ drive and right-click on it. Choose Extend Volume from the drop-down menu.
The Extend Volume Wizard opens. Click Next to begin the Extend Volume process.
4) To add all available space to your C:\ drive (Disk 0), you can keep the default selections and press Next, as shown in the following image:
The C:\ drive expands to the maximum available space.
5) To finalize the modifications, click Finish.
Verify disk space
The additional disk drive volume now displays in Computer Management and is available to use.
You can verify that the Extend Volume process worked correctly by loading the Computer Manager from the Server Manager and checking the disk size for the C:\ drive in Disk Management.