The Fastdfs of FASTDFS forum data in Chinaunix an efficient Distributed File system __ File storage System Fastdfs

Fastdfs Open Source Architecture version of the Chinaunix site in the link address, the moderator is Fastdfs's author

Http://bbs.chinaunix.net/forum-240-8.html

The FASTDFS server has two roles: Tracker (tracker) and storage node (storage). The tracker mainly does the dispatching work and plays the role of load balancing on the access.

Storage node storage files, complete file management of all functions: storage, synchronization and provide access to the interface, Fastdfs at the same time the metadata of the file management. The so-called file meta data is the file's related attributes, in the form of key-value pairs (key Valuepair), such as: width=1024, where the key is Width,value 1024. File metadata is a list of file attributes that can contain multiple key-value pairs.

Both the tracker and the storage node can be composed of one or more servers. The servers in the tracker and storage node can be added or offline at any time without affecting the online service. All servers in the tracker are equivalent and can be increased or decreased according to the server's pressure.

To support large capacity, storage nodes (servers) are organized by volume (or grouping). The storage system consists of one or more volumes, the files between the volumes are independent of each other, and the file capacity of all volumes is the file capacity of the entire storage system. A volume can consist of one or more storage servers, the files in a storage server under a volume are the same, and multiple storage servers in a volume play a role of redundant backups and load balancing.
When the server is added to the volume, the synchronized files are automatically completed by the system, and after synchronization is completed, the system automatically switches the new server to the online service.

Volumes can be added dynamically when storage space is low or is about to run out. Only one or more servers need to be added and configured as a new volume, which expands the capacity of the storage system.