rewrite this statement "Developing, testing, debugging, and studying the performance of cloud systems are quite complex. Management cost increases significantly as the number of sites increases. To address such problems, we need monitoring and reporting mechanisms. Monitoring basically monitors the SLA lifecycle. It also determines when an SLA completes and reports to the billing services. There are some services that monitor the cloud systems and produce health reports such as Hyperic HQ, which monitors SimpleDB, Simple Queue Service, and Flexible Payment Service, all offered by Amazon. It collects the matrix and provides a rich analysis and reporting