In this present study, series-parallel system composed of five subsystems with the following specifications were analyzed: subsystem 1 consists of two dissimilar clients that are connected to a single unit load balancer I which made up subsystem 2, whereas subsystem 3 consist of two active fog node working in parallel, subsystem 4 comprises of a load balancer II and sub-system 5 is made up of two similar units/components of cloud server. Cloud server, load bal-ancer, fog node and clients failure and repair rate are assumed to be exponentially distributed. The system is under four different scenarios as follows: Scenario 1 system with replacement at complete, scenario 2 system with replacement at partial failure and complete, scenario 3 system without failure detection and replacement repair at complete and lastly, scenario 4 system with undetected failure and replacement at complete. This system is susceptible un-der first order differential difference equation to formulate the expression of availability and MTTF. The steady state availability, MTTF, sensitivity and expected profit based on general were compared and presented. This study is important to system engineers, designers, plant management, developers and maintenance personnel in the suitable designing and analysis of maintenance policy or processes and also in the assessment of performance and safety of the systems in general during and after the burn-in period.