SLA Design from a Business Perspective

Abstract

A method is proposed whereby values for Service Level Objectives (SLOs) of an SLA can be chosen to reduce the sum IT infrastructure cost plus business financial loss. Business considerations are brought into the model by including the business losses sustained when IT components fail or performance is degraded. To this end, an impact model is fully developed in the paper. A numerical example consisting of an e-commerce business process using an IT service dependent on three infrastructure tiers (web tier, application tier, database tier) is used to show that the resulting choice of SLOs can be vastly superior to ad hoc design. A further conclusion is that infrastructure design and the resulting SLOs can be quite dependent on the "importance" of the business processes (BPs) being serviced: higher-revenue BPs deserve better infrastructure and the method presented shows exactly how much better the infrastructure should be.

Initial thoughts on business-driven IT management challenges in Cloud computing providers

“…Regarding specification and management of SLAs, Sauvé et al [9] present a method whereby the best values for Service Level Objectives (SLOs) of an SLA are chosen by considering the business perspective. However, the impact model proposed only includes business losses due to failure or performance degradation of IT components.…”

Predictable Scaling Behaviour in the Data Centre with Multiple Application Servers

“…Recent work by Sauvé et al discusses the matter of trying to convert low level knowledge of a system into SLA margins, in a multi layered model using the cost of the equipment and services to add an element of risk analysis to the problem [2]. They use the simplest kind of queue model to estimate capacity -this is understandable given the complexity of the problem.…”

“…Meeting the requirements set by SLAs, with variable demand and resources, has become a keen point of interest in the last year [2,3,4]. A common strategy for trying to determine this relationship is to opt for "over-provision", i.e.…”

Uncertainty in Global Application Services with Load Sharing Policy

“…The service provider wants to guarantee that users will gain access to their services within a Service Level Objective. Users are known to give up on slow services within just a few seconds and take their custom elsewhere [1].…”

“…Even if no formal Service Level Agreement (SLA) has been made, Service Level Objectives (SLO) are set by clients' demands: users will typically defect from a slow web-site after only a few seconds of waiting in order to look for an alternative [1], hence performance is directly related to profit.…”