  Owing to the massive growth in the storage demands of big data, Cloud Storage
Systems (CSSs) have been put forward to improve the storage capacity. Compared
with traditional storage systems, CSSs have lots of advantages, such as higher
capacity, lower cost, and easier scalability. But they are also with higher
complexity. In order to ensure CSSs to be reliable, it is necessary to prove
the correctness of CSSs management programs. In fact, we are going to verify
Block-based Cloud Storage Systems (BCSSs), since BCSSs are the most popular
CSSs.
  In this paper, the correctness of management programs in BCSSs have been
proven, and a verification framework based on separation logic is proposed to
finish the proven process. The main contributions are as follows. (1) A novel
framework with two-tier heap structure is constructed to reflect the
characteristics of BCSSs, and a modeling language is defined based on it. (2)
Assertions based on separation logic is constructed to describe the properties
of BCSSs. (3) The Hoare-style specifications are proposed to reason about the
BCSSs. The results demonstrate that the correctness and reliability of BCSSs
can be verified by the above proposed methods. Furthermore, the proposed
specifications is sound in the application of reasoning about BCSSs.
