The advent of the information age has brought new problems to people: the generation, storage and access of massive data. Therefore, network storage technology has emerged. Network storage technology is a common network term based on data storage. With the emergence of network storage technology, people's requirements on storage of massive data, data sharing and analysis, and data security and backup have been met. However, how to effectively guarantee the security of these data, ensure the timeliness of these data access and the rapid recovery of data in the case of system failure has become an important issue and difficulty at present.
Direct connection storage is the direct connection of a data storage device such as a disk array or tape library to a server or client via an extended interface. The DAS is server-centric, with no storage operating system, meaning that the storage device is part of the server, and I/O requests are sent directly to the storage device. The advantages of this approach are simple implementation, low cost and quick results. But storage management is tedious and repetitive, capacity is hard to reallocate, response times slow when the server is busy, and scalability performance is poor. NAS is different from DAS. Its storage device is not directly connected to the server, but directly connected to the network and connected to the server through the standard network topology. In this storage mode, the application and data storage parts are on different servers, respectively, application server and data server. The data server has its own operating system and can convert the "file.i /O" File storage request of the borrowed application server to "block.i /O" and send it to an internal disk. Different application servers can access the data server through the LAN interface, which realizes the data sharing between heterogeneous servers. NAS are characterized by storage independence, protocol independence, ease of management and good performance/performance ratio. However, since NAS and normal business access use the same network, they will cause mutual influence. When the amount of NAS is relatively large, the demand for network resources can be reduced through NDMP, and local backup and disaster recovery can be achieved. NDMP is an open protocol based on enterprise data management, which defines a network-based protocol and mechanism for controlling backup, recovery, and data transfer between primary and secondary storage. The NDMP structure is based on the client/server model in which data producers and consumers are considered to be servers or service providers, or data service providers; Backup management software is considered a client. You can only have one client per NDMP session, but you can have multiple servers. Storage area network concept. Storage area network. A SAN is a storage structure that connects a storage device and related servers through a dedicated transport channel. SAN mainly consists of three parts: storage device, special transmission channel and server. Like NAS, SAN also supports data sharing between heterogeneous servers, and SAN storage devices can be located in agreed geographic locations or extended to different locations. SAN and server are independent and peer, communicating with each other through high-bandwidth hubs or switches. The server can access any storage device in the SAN through a dedicated transport channel and use it as a local storage device. Communication between storage devices, betwe