Strategic optimisation of service systems with cold-standby parts using inventory policy

Ensuring the reliability of terminal servers is a cardinal concern in today's business operations, given the potential for system failures and resultant operational interruptions. One efficient strategy that has emerged is using cold standbys, inactive redundant components that spring into action when the primary system falters. There has been a lot of research on queueing systems and how they work with repairable servers, but there is still a clear need to combine these findings with the best way to order standby parts. This paper pioneers the development and detailed study of an M/M/1 queueing model outfitted with cold standby parts, regulated by an (r, q) ordering policy. Our investigation goes a step further, delving into customer behaviours and how server availability influences their strategic decisions, ultimately affecting the service provider's profit margin. By intertwining the principles of queueing systems with inventory theory, we propose a novel model that offers companies a refined strategy to maximise anticipated profit against the backdrop of potential server breakdowns. [Submitted: 17 April 2024; Accepted: 18 April 2025]