Generally, embedded operating systems, such as vxworks/Linux, are used, and some of them use windows CE.
NAS (Network Attached Storage) literally means a device that is connected to the network and has the function of data storage, so it is also called "network storage". It is a dedicated data storage server. It takes data as the center, completely separates storage devices from servers, and centrally manages data, thus releasing bandwidth, improving performance, reducing total cost of ownership and protecting investment. Its cost is much lower than using server storage, but its efficiency is much higher than the latter.
NAS is defined as a special dedicated data storage server, including storage devices (such as disk arrays, CD/DVD drives, tape drives or removable storage media) and embedded system software, which can provide cross-platform file sharing functions. NAS usually occupies its own nodes on the local area network, allowing users to access the data on the network without the intervention of application servers. In this configuration, NAS centrally manages and processes all data on the network, reducing the load of application programs or enterprise servers, effectively reducing the total cost of ownership and protecting users' investment.
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NAS itself can support various protocols (such as NFS, CIFS, FTP, HTTP, etc. ) and various operating systems. Through any workstation, using IE or Netscape browser, you can manage NAS devices intuitively and conveniently.
The difference between SAN and NAS:
SAN is a network, and NAS product is a proprietary file server or read-only file access device.
SAN is a private network, which is used as an I/O path between servers and storage.
SAN includes block-oriented (iSCSI) and file-oriented (NAS) storage products.
NAS products can be connected to storage devices through SAN.
The emergence of NAS
NAS is a simple computer with a single function, so its architecture is not as complicated as that of a personal computer, such as keyboard, mouse, screen, sound card, speaker, expansion slot and various interfaces. From the appearance, it is like a household appliance, which only needs a power supply and a simple control button. NAS is similar to a personal computer in architecture, but because of its simple function, it can eliminate many unnecessary connectors, control chips and electronic circuits, such as keyboard, mouse, USB and VGA.
Advantages and disadvantages of storage
Advantages:
NAS products are truly plug-and-play products. NAS devices generally support multi-computer platforms, and users can access the same documents through network support protocols, so NAS devices can be used in mixed Unix/Windows NT LAN without modification.
The physical location of NAS devices is also flexible. They can be placed in the workgroup, near the application server in the data center, or in other places, and connected to the network through physical links. Without the intervention of application server, NAS devices allow users to access data on the network, which can not only reduce the overhead of CPU, but also significantly improve the performance of the network.
Limitations:
NAS does not solve a key problem related to file servers, that is, bandwidth consumption during backup. Unlike a storage area network (SAN) that transmits backup data streams from a local area network, NAS still uses the network for backup and recovery. One disadvantage of NAS is that it transfers storage transactions from parallel SCSI connections to the network. This means that the LAN not only has to deal with the normal end-user transport stream, but also handles the storage disk requests including backup operations.
Because the stored data is transmitted through the ordinary data network, it is easily affected by other traffic on the network. When there is other big data traffic on the network, it will seriously affect the system performance; Because the stored data is transmitted through ordinary data network, it is easy to cause security problems such as data leakage;
Storage can only be accessed as a file, but not as a physical block like a common file system, which will seriously affect the efficiency of the system in some cases, such as large databases can not use NAS.
Job classification
1. Electrical server
The electric server is the lowest product in the NAS series equipment. The electric server is not a special additional storage device. They provide storage locations for the network, but they are relatively cheap because there are no redundant and high-performance components. In a workgroup environment, electrical servers play many roles. Typical services include network address translation (NAT), proxy, DHCP, email, Web server, DNS, firewall and VPN.
2. workgroup NAS
Workgroup-level NAS is especially suitable for small and medium-sized companies with relatively low storage requirements, generally ranging from several hundred GB to 1TB. Companies running e-commerce software or large databases will need several terabytes of storage space, and they use medium-sized NAS. Generally speaking, when upgrading from workgroup to medium-sized NAS, you will find that hot-swappable drives and some equipment boxes can hold additional drives or more recovery products, which enhances the management function and slightly increases the system complexity.
3. Medium NAS
The medium-sized NAS solution we are talking about provides better scalability and reliability, and has similar advantages to low-end NAS, such as convenience, dedicated storage space and simple installation and management processes. Compared with electrical servers and workgroup NAS, the cost of these NAS devices is obviously much higher.
4. Large NAS
The scalability, high availability and redundancy of such storage devices are very important. These devices must also provide the performance of high-end servers, flexible management and the ability to interact with heterogeneous network platforms.
Main applications
1. Office Automation NAS Solution
Office Automation System (OA) is the focus of government agencies and enterprises' information construction. The management and operation of modern enterprises and institutions can not be separated from computers and local area networks. When enterprises use the network for daily office management and operation, they will produce daily office documents, drawing documents, ERP and other business data and many personal documents. The traditional internal LAN generally has no file server, and the above data are generally stored on employees' computers and servers, and there is no suitable equipment as its backup and storage application. Due to the low security level of personal computers and uneven safety awareness of employees, important information is easy to be stolen, maliciously destroyed or lost due to hard disk failure.
From the analysis of data storage in enterprises and institutions, it can be seen that in order to make the internal data of enterprises and institutions be managed uniformly and applied safely, there must be a safe, economical, convenient and simple physical medium to store and back up the internal data of enterprises. NAS network storage server is a specially designed file storage and backup server, which can manage the data in the network reasonably, effectively and safely, and can be used as a backup device to automatically back up databases and other application data to NAS irregularly.
2. Tax NAS solution
What the tax industry needs is an integrated system that integrates business, information and decision support. Industry business system is mainly tax collection and management information system, as well as tax business information and general business information. The whole system combines administrative office information, auxiliary decision-making information and business system to form a general integrated system platform, thus forming a complete, integrated and integrated tax business management system.
Business data, daily office documents and data mail systems in the tax industry are very important. Once the data is lost, it will bring trouble to the daily work and tax work of the whole region. Ensuring the safe operation and application of the whole data has become a realistic problem that the tax industry must solve. The solution to this problem is to store or back up these data in a safe, fast and convenient application environment to ensure the safe operation of tax industry data.
In order to solve the problem of data backup and storage reasonably, NAS network storage server can be used to store and backup business data and daily office data. In the service host, the information in the database is directly backed up to NAS through the incremental data backup function. Together with the business data in the LAN, the daily office documents of the staff or the data based on CD-ROM, it can be stored on the NAS server so that the staff can use and browse these data at any time. After using NAS, administrators can effectively and reasonably arrange and manage their own internal data, separate data files from other network machines, realize decentralized storage of data, and uniformly manage data environment systems.
3. Advertising NAS solution
Advertising design industry is a comprehensive service industry integrating market research, marketing strategy, creative production, design execution, post-production and media release.
The data storage mode of many advertising companies is relatively backward, with high cost and low efficiency. The main problem is poor data security. The overall data volume is large, and a large amount of old data is difficult to store and manage; There are multiple operating system platforms, and the complex equipment makes it difficult to share and manage the stored data, which is inefficient; The resignation of the advertising designer caused the innocent loss of design materials. NAS is used to store and back up the business data in the advertising design industry network, so as to realize centralized storage, backup, analysis and sharing of data. According to the different requirements of design and research institutions for different data, we should make full use of existing data and reasonably build a data storage platform for advertising design industry, so as to improve the transmission speed of information materials, save time and improve work efficiency.
4. Education NAS solution
Since the "school-to-school communication" project was put forward, in order to adapt to the development of the information age in time, all schools are actively building their own campus networks. With the gradual implementation of the "school-to-school communication" project, "resource communication" has become the focus of the next information construction, which is embodied in the fact that schools need a lot of resource information to meet the needs of students and teachers. With the increasing data resources on campus, the physical media that needs to store data has a large storage space and security, and has a very fast transmission rate to ensure the safe and fast access of the whole data.
In the process of campus network construction, the focus is on the construction of network system, equipped with a large number of advanced equipment, but the teaching application resources on the network are relatively scarce. The original storage mode will show many disadvantages when increasing teaching resources: because all the educational resources in the traditional network application of schools are stored on one server, the cost of a high-performance and high-scalability server is higher; The access service of teaching resources will compete with the application service for system resources, which will lead to a significant decline in system service efficiency; The system failure of application server will directly affect the security and availability of resource data, which will bring inconvenience to school teaching.
In order to solve these problems, NAS devices can be introduced to realize centralized storage and backup.
(1).NAS provides an efficient and low-cost resource application system. Because NAS itself is an independent network server, it can be flexibly deployed on any segment of the campus network, which improves the efficiency and security of resource information service, and has good scalability and low cost.
(2) Provide flexible personal disk space services. NAS can create a personal disk space for each student user, which is convenient for teachers and students to find and modify their own data.
(3) Provide an environment for online data backup. NAS supports external tape drives, which can effectively transfer data from the server to the external tape drives, ensuring safe and fast data backup.
(4) Effectively protect resource data. NAS has automatic logging function, which can automatically record the access information of all users. Embedded operation management system can ensure that the system will never collapse, ensure the continuity of resource services and effectively protect the security of resource data.
5. NAS scheme for medical data storage
As a social medical service institution, patient's medical record management is very important. Film based on CT and X-ray should be converted into digital information by film digitizer and stored for future search. The amount of data in these films is very large and very important. The safe storage of these films, the rapid acquisition and effective utilization of management data and information are important factors to improve work efficiency, and are also key issues in hospital information construction. According to the survey, a hospital has a monthly data volume of nearly 500GB, so it is not enough to store such a large amount of data by computer alone. Some hospitals will use burners to burn past data and pictures to CD for storage, but this storage solution is time-consuming and inefficient. Hospitals need a physical medium with large capacity, high security, convenient management and fast data query to store and manage these data safely and effectively. Using NAS solution can safely, conveniently and effectively store and manage these digital pictures in hospital radiology department, thus shortening the time of data storage and retrieval and improving work efficiency.
6. NAS solution for manufacturing industry
For the manufacturing industry, all kinds of market data, customer data, transaction history data and social comprehensive data are the vital assets of the company and the lifeblood of enterprise operation. On the basis of enterprise data electronization, it has become a key factor for the success of enterprises to protect the key data of enterprises and make rational use of them. Therefore, centralized storage, management and backup of all kinds of data in manufacturing industry, according to the different requirements of enterprises for different data, so as to build a reasonable enterprise data storage platform. The storage mode of NAS is more suitable, which can realize centralized storage, backup, analysis and sharing of data, and make full use of existing data on this basis to meet market demand and improve competitiveness.
To sum up, NAS has great advantages in data management, which can fully reflect its value in some network environments with rapid data expansion, high requirements for data security and heterogeneous platform applications. In addition, NAS is very cost-effective, and is widely used in various application environments from small and medium-sized enterprises to large and medium-sized enterprises.
Basic protocol
Some people think that the essential difference between NAS and SAN lies in Ethernet and FC, and their fate depends on TCP/IP protocol. SAN uses SCSI transmission on FC. ISCSI, as a new protocol to connect IP and SCSI (which has been used in FC), is regarded as a major event that affects the fate of SAN. These essential differences are from the perspective of network architecture. For many users who are concerned about the performance difference between NAS and SAN, the essential difference between them also lies in the realization of file reading and writing.
NAS uses NFS(Sun) to communicate with Unix camp, and CIFS communicates with NT and Unix, which also shows that NAS is a "file-level" reading and writing operation based on operating system, and the access request is based on "file handle+offset". Handles are smaller units than processes, and are usually used for communication between processes, resource location, etc. The interface between computer and storage in SAN is the underlying block protocol, which is located according to the "block address+offset address" of the protocol header. From this perspective, SAN is born with the storage virtualization function of heterogeneous storage integration. Let's introduce the soul of NAS files * * *-NFS and CIFS.
NFS (Network File System) is a method of sharing disk files between Unix systems. It is a file system protocol that supports applications to access data located in the disk of a client server through the network. In fact, it includes many protocols. The simplest network file system is the network logical disk, that is, the file system of the client operates the remote logical disk through the network, such as IBM SVD(*** virtual disk). Now NFS(Sun) developed by Sun Company is widely used among Unix hosts, which can realize file data exchange among all Unix systems and gradually become the standard for sharing resources among hosts. In contrast, the network file system adopted by SAN, as a high-level protocol, needs a special file server to manage disk data. The client accesses data in the form of logical file blocks, and the file server uses block mapping to access real disk blocks and manage disk formats and metadata.
CIFS was developed by Microsoft to connect Windows clients and servers. After the secondary development of Unix server manufacturers, it can be used to connect Windows clients and Unix servers and perform tasks such as file sharing and printing. Its earliest origin is NetBIOS, which is an API developed by Microsoft to realize the sharing of name resources based on Windows in LAN. Later, NetBEUI protocol and NBT(NetBIOS OVER TCP/IP) protocol based on NetBIOS came into being. NBT protocol further developed into SMB (Server Block Protocol) and CIFS (Common Internet File System) protocols. Among them, Windows system uses CIFS, Unix and Linux widely use SMB, and they can communicate with each other. SMB protocol is also called LanManager protocol. You can enjoy CIFS by communicating with SMB-enabled servers. The Microsoft operating system family and almost all Unix servers support SMB protocol /SMBBA software package.
But the recent news is a bit bad-Microsoft has withdrawn its support for CIFS protocol in key applications such as Exchange. Microsoft said on its website that the CIFS protocol requires data to pass through customers' network devices, which easily leads to performance bottlenecks. This move was attacked by insiders.
Jeremy, one of the developers of SAMBA open source software, said that the fear of Linux and trying to use the advantages of its desktop operating system to protect the sales of Windows server operating system are the real reasons why Microsoft rejected the CIFS protocol. Network Appliance (one of the major manufacturers of NAS equipment) also said that this measure of Microsoft was "irrational and greedy".
Network procurement
For users who are ready to set up a network, because NAS is already a file server with superior performance, using NAS devices in the network means that it is not necessary to buy a file server in the traditional sense, which can greatly reduce the total cost of ownership of users. At the same time, NAS devices can also cooperate well with application servers to improve the overall performance of the network.
For users who have established a network, NAS equipment can be used in conjunction with the original file server, which greatly protects the user's upfront investment. NAS can also be used with multifunctional servers, which can reduce the working pressure of servers and save more time for other applications, thus improving the performance of the network.
Once the user determines the basic architecture of the storage system, we need to choose products. Capacity and price are of course one of the key points to consider, but these two factors are very easy to draw conclusions, so it will not be difficult for users to buy, as long as they are careful not to let the investment equipment idle and leave some room for upgrading. The real difficulty of product procurement lies in a comprehensive investigation of its internal performance and functions, including data security, performance, connectivity, manageability and additional functions.
Security data security refers to the expectation of all kinds of unexpected errors and unexpected situations and the preventive or remedial measures taken in the design of storage devices. Users should note that the storage system is a complex system from soft to hard, so the evaluation of data protection ability should consider the whole system.
Performance For NAS products, the main performance indicators are OPS and ORT, which respectively represent the number of concurrent requests per second and the average response time of each request. It is generally believed that NAS has excellent performance in the environment where small files such as Web, e-mail and database are frequently read and written.
Manageability is one of the important characteristics that any IT product must have. First of all, users should consider whether the management functions or methods provided by products are practical and reliable, such as remote Web management and automatic alarm.
The ability to work together is not a problem for NAS, because NAS devices are only accessory devices. However, users should carefully consider this issue, especially in the case of high system security and full of various security authentication mechanisms.
Storage comparison
Traditional database servers are usually equipped with large-capacity memory, and clustered high-end CPU and local attached storage form a huge and comprehensive complex architecture. The main reason for this configuration is that the database server must perform various services at the same time, such as printing service, file name service, file service, database, routing, tape backup, disk array RAID and public service. All services will consume the memory and CPU resources of the server. In the process of multilevel data processing, processors and disk controllers may compete for access to main memory addresses, which greatly reduces the efficiency of their core database services. Therefore, how to optimize database services in hardware configuration has become a top priority.