Cloud providers offer an array of storage services that, represent, different points along the performance, cost, and durability spectrum. if all application desires the, composite benefits of multiple storage tiers, then it must manage the complexity of different interfaces to these storage services and their diverse policies. We believe that, it, is possible to provide the benefits of customized tiered cloud storage to applications without compromising simplicity using a lightweight middleware. Tit tiffs paper, We introduce Tiera a middleware that enables the provision of multi tiered cloud storage instances that are easy to specify, flexible, and enable a rich array of storage policies and desired metrics to be, realized. Tiera's novelty lies in the first-class support for encapsulated tiered cloud storage, ease, of programmability of data management policies, and support, for runtime replacement and addition of policies and tiers. Tiera enables an application to realize a desired :metric (e.g., low latency or low cost) by selecting different storage services that constitute Tiera instance, and easily specifying a policy, using event and response pairs, to manage the life cycle of data stored in the instance. We illustrate the benefits of Tiera through;A prototype implemented on the Amazon cloud. By deploying unmodified MySQL database engine and;A TPC-W WEAL bookstore application Tiera, we are able to improve their respective throughputs by 47%-125% and 46%-69%, over standard deployments. We further show the flexibility of Tiera in achieving different, desired application metrics with minimal overhead.