Metadata (such as a file directory, I-node, and idle block mapping table) indicate the structure of the raw store. Metadata provides a pointer and descriptor, linking the sectors on the disk into files and distinguishes them. In order to maintain reliable storage for a long time, the file system must have a non-expected system crash, such as power failure and operating system failure, to ensure the integrity of metadata. Since similar crashs typically result in the loss of all information stored in the volatile main memory, the information stored in the non-volatile memory (eg, a disk) must always have sufficient consistency to determine the file system. Consistent. In particular, the mirroring of the file system can never include a suspension pointer, and it is not enough to lead to a resource ownership pointer, or an unprecedable activity resource. Maintaining these principles The small metadata objects are usually updated sequentially (or by atomic operation packet).
