Principle of data storage technology
Source: Shangpin China |
Type: website encyclopedia |
Time: 2015-06-15
In the past 40 years, great changes have taken place in the field of computing, but the importance of computer processing and data generation has not changed. Once data is lost, all computing power becomes worthless. Just like capital or intellectual property, data has become a wealth that can be shared and needs to be stored and protected. Data storage and storage management technology originated from the terminal/host computing mode in the 1970s. At that time, because the data was concentrated in Beijing Website Design Therefore, the hard disk and tape connected to the host are the main storage and backup devices. Since the 1980s, with the development of personal computers, especially the emergence of the client/server model, data storage has gradually become decentralized. At this time, the file server and database server on the network are often important data centers. There is also a certain amount of data on the client, and the distribution of data causes the complexity of data storage management. In the 1990s, the rapid development of the Internet also led to revolutionary changes in storage technology. This change is mainly reflected in three aspects. First, the storage capacity expanded rapidly, and now P level (IP=250) storage has become common; Secondly, the duration of data is also increasing. The network data on the Internet must be available 24 hours a day, 7 days a week, 365 days a year; Finally, the diversification of data, geographical dispersion, and protection of important data all put forward higher requirements for data storage management. In this process, disk storage undoubtedly plays an important role. Although the capacity of disk storage is increasing, the demand for users to store large amounts of data is also rising, which requires the expansion of disk storage. Currently, the methods used to expand disk storage mainly include redundant arrays of Inexpensive Disks (RAID), Directly Attached Storage (DAS) Network Attached Storage (NAS) and Storage Area Network (SAN). 1. Redundant disk array Disk array is a system that integrates several hard disk drives according to certain requirements, and the entire disk array is managed by the array controller. The redundant disk array technology was proposed by the University of California, Berkeley, in 1987. The original development purpose was to combine small inexpensive disks to replace large expensive disks, so as to reduce the cost of mass data storage; At the same time, we also hope to use redundant information so that disk failure will not cause loss of data access, thus developing a certain level of data protection technology to improve data security. RAID technology has become an industrial standard, divided into several different levels, which can provide different speeds, security and cost performance. At present, RAID levels widely recognized by the industry are defined as RAID 0, RAID 1, RAID0+1, RAID 3 and RAID 5. 2. Direct external storage The storage mode of DAS is the same as the storage architecture of personal computers. External storage devices are directly attached to the bus inside the server, and data storage devices are part of the entire server structure. DAS storage mode is mainly applicable to the following environments. 1) Small network Because the network size is small, the amount of data storage is small and not very complex, so this storage method will not have a great impact on the server. This storage mode is very economical and suitable for enterprise customers with small networks. 2) Geographically dispersed network Although the overall network size of the enterprise is large, it is geographically dispersed, and it is very difficult to interconnect them through SAN or NAS. At this time, servers of each branch can use DAS storage mode to reduce costs. 3) Special application server On some special corner servers, such as cluster servers or original partitions used by some databases, the storage device is required to be directly connected to the application server. 3. Network attached storage NAS uses a file server that is independent of the server and developed separately for network data storage to connect storage devices, forming a network of its own. In this way, the data storage is no longer attached to the server, but exists in the network as an independent network node and can be shared by all network users NAS has the following advantages. (1) Plug and play: NAS is an independent storage node in the network, independent of the user's operating system platform. (2) Simple storage deployment: NAS does not rely on the general operating system. Instead, it uses a simplified user oriented operating system designed specifically for data storage. It has built-in protocols required for network connection, so the management and setup of the entire system are relatively simple. (3) Storage device location is very flexible. (4) 'Easy management and low cost: The NAS data storage mode is designed based on the existing enterprise Ethernet. It communicates according to the TCP/IP protocol and transmits data in 1/0 of the file. The disadvantages of NAS are low storage performance and low reliability. 4. Storage Area Network In 1991, IBM introduced ESCON (Enterprise System Connection) technology in the S/390 server. It is a connection method for servers based on optical fiber media and with a maximum transmission rate of 17 Maps to access storage. On this basis, it further introduced ESCON Director with stronger functions, and built a set of the most original SAN system. SAN storage mode creates the networking of storage, and the networking of storage conforms to the trend of networking of computer server architecture. The supporting technology of SAN is Fibre Channel (FC) technology FC technology supports a variety of advanced protocols such as HIPPI, IPI, SCSI, IP, ATM, etc. Its biggest feature is to integrate the communication protocol of the network and equipment with the transmission physics Media isolation enables multiple protocols to be transmitted simultaneously on the same physical connection. A SAN built with Fibre Channel consists of the following three parts. ·Storage and backup equipment: including tape, disk, optical library, etc ·Fibre Channel network connection components: including host bus adapter card, driver, optical cable, hub, switch, bridge between Fibre Channel and SCSI (Small Computer System Interface) ·Application software and management software: including backup software, storage resource management software and storage device management software. Advantages of SAN: (1) Network deployment is easy. (2) High storage performance. Because SAN adopts Fibre Channel technology, it has higher storage bandwidth and significantly improved storage performance SAN's Fibre Channel uses full duplex serial communication to transmit data, with a transmission rate of up to 1062 5Mbps. (3) Good scalability. Because SAN adopts network structure, it has stronger scalability. The optical fiber interface provides a connection distance of 10km, which makes it very easy to realize physical separation and storage not in the local computer room. NAS and SAN are literally very similar. They are both new data storage models. NAS is usually a server cluster, such as application server, mail server, etc. Storage devices are easy to attach to this system. SAN is mostly deployed in e-commerce applications, and a large number of data backups and other businesses need to be stored and transmitted frequently on the network; SAN can unload a large amount of data traffic from the user's primary network, which can free the network from data congestion. The functions of SAN and NAS are complementary and can coexist in a network.
Source Statement: This article is original or edited by Shangpin China's editors. If it needs to be reproduced, please indicate that it is from Shangpin China. The above contents (including pictures and words) are from the Internet. If there is any infringement, please contact us in time (010-60259772).
