When we talk about the scaling of the HANA system it is all related to hardware resources. We have different scenarios in which we need to consider scaling. Scaling can be divided into two categories.
Let’s assume we have running HANA DB server and now there is a requirement to increase the resources of current hardware this is called a scaleup scenario. In this scenario, If the hardware capability can be checked from vendors.
In this case, we have to increase the resources by adding up one or more hosts. This setup can be achieved from the installation phase and later as well. In Scale-out we have multiple requirements, but I will mention two most commonly used which are Worker node and stand by the node.
The worker node will be added as a parallel system and will handle the database requests. This is used to achieve more system performance.
Standby node will add up as a backup system and will not entertain any requests, it is also called a failover scenario. When the worker node will get down the standby node take over to all services.
In scale-out scenario, installation path should be accessible to all the systems which is Hana/shared by default. Because it is one database with multiple nodes. usr/sap will be separate for all the nodes.