A Flexible and Cost-Effective File-Wise Reliability Scheme for Storage Systems

This work presents a new scheme of reliability mechanism in storage systems. The new scheme defines reliability and protects data in the scope of file, which is very different from traditional strategies, which protect data in the scopes of storage block or the whole device. The scheme provides the possibility to store highly reliable files and normal ones under the same file system, increasing flexibilities and decreasing costs of storage systems. To implement this scheme, Linux virtual file system (VFS) layer has been modified to perform reliability related operations during I/O calling paths and provide new interfaces for file systems to define their own reliability methods. A modified Ext2 file system with different levels of reliability has also been built as an example design of the new scheme. Depending on reliability levels, files in the example design are protected by parity check and Reed-Solomon Code of different code rates, which incur different overheads.