An Approach Of Optimizing File System Using Application-Oriented Semantics

Personal data is growing at ever increasing rates, fueled by a growing market for personal computing solutions and dramatic growth of available storage space on these platforms. File system as the base data management facility in operation systems for personal computer becomes more and more complex. File system metadata accessing performance is reduced due to the fairly complicated file system namespace.Complex namespace handling is important to file system performance. This work introduces a method for managing file system namespaces in an application-oriented way.We first use a popular application Apache Web Service as the case for tracing the relationship between applications and their files. The result of tracing file system shows that application oriented semantics actually exists, how to extract the application oriented semantics and proves that most of the applications only focus on a small part of the whole file system namespace. Then we make use of these application semantics to effectively simplify the namespace that applications must face, thus improve both the metadata accessing performance and file semantic prediction accuracy. We build a prototype file system for evaluating our method, analysis the potential problems and demonstrate the power and flexibility through a series of case studies, with a focus on how to manage file system namespace. In our prototype file system, we use FUSE which is a file system framework in userspace to provide file system function interface, use XML to represent file system metadata, use BDB XML database to store metadata XML files and use XML DOM tree to represent file system sub-namespace for a certain type of process.Our performance evaluation shows the overall gain is up to 30%~50% towards"raw"namespace which also using FUSE framework to some applications.