Abstract: Considering the sensitive information security issue on the traditional cloud storage platform,  It divided metadata management into two parts , the client side metadata managementSub-Metadata Server(Sub-MS) and the cloud side metadata management-Core Metadata Server(CMS). Sub-MS aimed to extract independently ，maintain，read and write and store the metadata with sensitive information, which used the random redundancy algorithm in maintaining mapping relations, based on the redundancy between files and data blocks, to improve the files storage security. At the same time, Sub-MS used the request synchronism strategy to keep the consistency of mapping relations from data blocks to Data Server(DS）between Sub-MS and CMS, to insure the stability and reliability of the whole storage system. With multi-user concurrent access, the experiment about performance of reading and writing for the data sets of different sizes indicates that compared with HDFS and GFS, SISM still has good reading and writing performance and data persistence capabilities in managing metadata of sensitive information by itself.

Key words: cloud storage; data security; privacy preserving; selfmanagement; metadata