Metadata Management In Object-Based Storage System

The rapid development of network technology and digital information has stimulated the emergence of mass information applications. The current storage architecture becomes the performance bottleneck. The rapid development of magnetic store technology leads to the situation that the I/O performance falls behind the speed of CUP and memory. However, the traditional block access interface can not change this situation. The Object-Based Storage (OBS) providing object-based access interface is expected to change the situation. And its metadata management becomes new challenges and research topics.The object-based storage system contains three major components, namely are clients, Metadata Server (MDS) and object-based storage nodes. Data is stored on the nodes that can be directly accessed through the network, while metadata is managed separately by one or more specialized metadata servers. The position of the MDS in the object-based storage system is very important, and it can be a potential bottleneck of the system. In the object-based storage system files are mapped onto one or more data objects stored on the nodes. The policy for object allocation is a critical aspect affecting the overall system performance. Hashing and fragment-strip are two common techniques used for managing objects, but both have their disadvantages and advantages. We present an efficient algorithm that combines the advantages of these two approaches while avoiding their shortcomings. The key factors which can impact the performance in the objects allocation are also be discussed.The design of MDS in object-based storage system and the organizing and management of metadata are also very important. The MDS in our system uses Lightweight Directory Access Protocol (LDAP) to store the metadata. And we design data allocation and data conversion modules especially for it. We also build buffers to optimize the performance. We test the system and prove that our object allocation algorithm is effective and the buffers optimize the performance.