Shared OS

Shared operating system plays a vital role in providing hosted SAP model with features like high availability and scalability. OS sharing in hosted SAP typically means that multiple servers would run using one single file of important parts of underlying OS. The shared files are mounted in read-only format so that no application server would be able to make any changes into the file. Files used by the server are mounted in server-specific area on the storage with read / write attributes. Shared OS is placed on a network storage or SAN to overcome the limitation of server failures due to hardware.

The system is further divided into Control nodes & application nodes. Control nodes are responsible to manage the entire application infrastructure and services over it. The control node, also known as a control centre does not have any SAP application installed. It only has the operating system installed on it. Application nodes are the ones that provide CPU and RAM to run the database queries as well as the SAP application. Then there is a Primary Application node which normally identifies the boot interface through hardware address and assigns an IP address to it, transfers the required files from shared OS on network to boot the system. The files that are shared with other nodes are mounted with read-only attribute.