I'm considering enabling load balancing on our data gateway clusters for Power BI, where we have two servers in a cluster, and the secondary is configured as a failover for the primary (only operational when the primary is offline). I was wondering how likely in the real world it is that using load balancing to push traffic through both servers would end up reducing high availability compared to only using the one, considering the following scenario:
- Assume a constant stream of traffic generated by application
- While there is no load balancing, one server does all the work and defines the capacity limits for the operation. If it fails, the other server picks up the work and because of identical specs, can handle the traffic as expected. Monitoring is configured so that an alert is triggered when either server hits 80% capacity, so scaling can take place before bottlenecks are hit.
- Load balancing is switched on, both servers are now processing traffic, and traffic increases to >50% capacity on both servers. One fails, and now the remaining server has to process >100% of its capacity, resulting in request delays or failures. At no point with either server were monitoring alerts triggered.
I suppose I could rephrase my question as 'does using load balancing to handle increased traffic instead of scaling the servers up reduce the redundancy required for high-availability?'