After installing Oracle Linux 6.5, 6.6, or 7, you should register your system and activate your subscription with Oracle to receive automatic updates to the software. This will ensure that the server is running the latest version of the operating system. For instructions, go to:
http://www.oracle.com/technetwork/articles/servers-storage-admin/yum-repo-setup-1659167.html
After you have updated your server with the latest updates, be sure to reboot your server before you use the operating system. In addition to ensuring that your server has the latest improvements to the Oracle Linux operating system, updating your server to the latest updates will ensure that it is running the latest version of the Unbreakable Enterprise Kernel (UEK) for Linux, which is needed for the proper operation of the optional NVMe storage drives, if installed.