Windows Storage Server 2012 R2 Standard Iso Download Extra Quality 'link' -

: If your organization has a volume license agreement, you can download the ISO from the VLSC "Download and Keys" section .

Because this OS is heavily outdated, you should strongly consider transitioning to a modern, supported ecosystem. Windows Server 2012 R2 | Microsoft Evaluation Center : If your organization has a volume license

Since 2012 R2 is , consider: