What is metadata (meta data)

1. What is meta data
The data in any file system is divided into data and meta data. Data refers to the actual data in the normal file, while the meta-
Data refers to system data that describes the characteristics of a file, such as access rights, the owner of the file, and the file data
Distribution information for blocks (Inode ...) Wait a minute. In a clustered file system, distribution information includes the location of the file on disk and the location of the disk in the cluster. The user needs to manipulate a file must first get its metadata to navigate to the location of the file and get the contents of the file or related properties.
2. Meta Data Management method
There are two ways of managing metadata. Centralized management and distributed management. Centralized management means that there is a node in the System specialized division metadata management, all metadata is stored on the node's storage device. Before all client requests for a file, the metadata must be requested for that Meta Data Manager. Distributed management means that the metadata is stored in any node of the system and can be migrated dynamically. The responsibility for metadata management is also distributed across different nodes. Most clustered file systems use centralized metadata management. Because centralized management is simple and easy to maintain, it can provide more satisfying performance in certain operation frequency. The disadvantage is a single failure point problem, if the server fails, the entire system will not work properly. Moreover, when the operation of metadata is too frequent, centralized meta-data management becomes the bottleneck of the whole system performance.
The benefit of distributed metadata management is that it solves a single point of failure for centralized management, and performance does not bottleneck with frequent operations. The disadvantage is that the implementation of complex, consistent maintenance complex, has a certain impact on performance.

What is metadata (meta data)