A computer implemented method and a secure relational file system (SRFS) for storing and managing data for backup and restore are provided. The SRFS receives data, generates first metadata including file-to-sector mapping information, splits the data into fixed sized data chunks (FSDCs), generates second metadata including logical boundaries used for splitting, creates fixed sized data blocks by prepending the second metadata to the FSDCs, splits each FSDC into variable sized data chunks (VSDCs), generates third metadata including unique identifiers (UIDs) for the VSDCs, creates variable sized data blocks (VSDBs) by prepending the third metadata and the second metadata to each VSDC, identifies unique variable sized data chunks (UVSDCs) of the VSDBs using the UIDs, stores the UVSDCs in chunk files, and stores the first metadata, the second metadata extracted from the VSDBs, and storage locations of the UVSDCs with the third metadata of the UVSDCs and duplicate VSDCs in databases.