An Approach to Identify and Monitor SLA Parameters for Storage-as-a-Service Cloud Delivery Model

Cloud computing is an emerging technological paradigm that follows pay-as-you-use model. By this model, the consumers are charged according to the usage without regard to where the services are hosted or how they are delivered. Usually cloud services are offered as various delivery models among which Storage-as-a-Service cloud is gaining interest in recent time. In this model, raw (block) storage is offered as a service. Like any other utility services, cloud negotiates its service levels and guarantees with its consumers by establishing Service Level Agreements (SLAs). SLA is important in any provider-consumer interaction as it defines a formal basis for performance and availability the provider guarantees to deliver. It consists of a set of measurable attributes called SLA parameters which are established by some objectively measurable conditions, termed as Service Level Objectives (SLOs). However, the SLAs provided by the present day state-of-the-art clouds are relatively biased towards vendors and do not provide any formal method of verifying if the guarantees are complying or not. This paper attempts to identify the SLA parameters for Storage-as-a-Service cloud delivery model and proposes a monitoring framework for compliance checking.