Measurement of Cloud Computing Services Availability

Recently we are witnessing the engagement of cloud computing services such as emails, web services, mobile application, sharing data-stores and many others. Huge number of companies, customers and public institutions are considering the migration to the cloud services. The topical questions behind this effort is the efficiency and measurement of the QoS - Quality of Services of the cloud computing utilisation. This paper is focused on the problematic of measuring and monitoring service availability in Cloud Computing. It deals with the Service-Level Agreement (SLA) monitoring approaches and frameworks. Furthermore it presents a new approach of the cloud service availability monitoring from the client-centric perspective. On the basis of the client-centric approach a new solution was designed, implemented and tested on a sample cloud environment.