Storage backup technology of data storage guide

Backup | Data storage Backup technology generally includes hardware technology and software technology, hardware technology is mainly tape drive technology, software technology is mainly general-purpose and special backup software technology.

Tape Drive Technology:



Both hard disk technology and optical technology are not suitable for data storage backup, only tape drive technology is truly appropriate for data storage backup areas. In fact, tape drive technology has long been the preferred unique data storage backup technology, since tape media not only delivers high capacity, reliability, and manageability, but is much cheaper than CD-ROM and disk media.

As a backup device, tape drive technology is also evolving. The current market of the tape drive, according to its record, can be grouped into two categories: one is the data flow tape drive, the other is a spiral-scan tape drive.

Data flow technology originates from analog audio recording technology, very similar to the principle of tape recorder. It records data by contacting a single or multiple static magnetic head with a high-speed motion tape. The disadvantage of this technique is that the tension on the tape is high and the durability is poor. The data flow tape drive is divided into QIC (Quarter-inch-cartridge, 1/4-inch) and 1/2-inch two, by tape width. 1/2-inch tape drive is a multi-head reading and writing, its high data transmission rate, large capacity. The 1/4-inch tape drive is a single head read and write, after each track, through the jump track to do the reverse record, record and retrieval speed are relatively slow.

Spiral scanning technology originates from analog video recording technology, much like the tape principle of VCR. It is contrary to the data flow technology, the tape is around the drum, the tape is moving very slowly, the magnetic drum is rotating at high speed, the magnetic head on both sides of the drum is also high-speed scanning tape for recording. When it does not receive the command to move the tape within a certain period of time, it relaxes the tape and stops rotating the drum to prevent unnecessary media abrasion and to avoid prolonged tension in the medium. Therefore, the technology has the characteristics of high reliability, high speed and high capacity.

IDC's research report shows that the current popular tape drive technology is Dc2000/travan tape drive, QICDC6000 tape drive, 8mm tape drive, DLT tape drive, DAT tape drive and mammoth tape drive. Here is a brief introduction to each.

QIC Tape This is a 1/4-inch bandwidth, cassette tape with box, also called 1/4-inch tape. It has two kinds of specifications, namely DC6000 and Dc2000/travan. The drive of the DC6000 tape is 5.25 inches, it is recorded vertically with a very simple drive device, but the data tape structure is very complex and expensive. It cannot compete with 4mm and 8mm tapes in a market with a capacity above 1GB. Dc2000/travan tape drives are only 3.5 inches, drive prices are low, generally do not have hardware data compression and write-read function, and the use of medium cost is also high. This product may be appropriate for desktop computer users with low performance requirements, but not many users.

The DLT Technology DLT (Digital Linear tape-Digital linear tape) technology originates from a 1/2-inch tape drive. 1/2-inch tape drive technology appears very early, mainly for real-time data acquisition, such as the exchange of information on the program-controlled switchboard records, seismic equipment, such as vibration signal records. The DLT tapes are jointly developed by DEC and quantum companies. Because of the large size of the tape, the DCT tape drive is all 5.25 inches in full height format. DLT products are mainly located in medium and Advanced Server market and tape library system due to their high capacity. DLT tapes have a capacity of 35GB per box and lower unit capacity costs.

4mm Technology 4mmDAT is also known as digital Audio tape technology (Digital Audio Tape). The early DAT technology was used primarily for sound recording, and was later applied to the data storage field as the technology improved. The 4mm dat experienced three technical stages of DDS-1, DDS-2 and DDS-3, with a capacity span of 1GB-12GB. 4mmDAT has developed rapidly in previous years due to its small size and proper capacity, and has been applied more in small networks. At present HP has introduced the use of DDS-4 standard, capacity of 40GB tape drive.

Because the tape storage system uses helical scanning technology, the tape has a high storage capacity. DAT tape systems generally use the read-write and compression technology, which improves the reliability and data transmission rate of the system, and improves the storage capacity. DAT tape and drive manufacturers are more, users have a greater choice of opportunities, is a promising data storage backup products.

8mm technology based on spiral scanning recording technology 8mm products developed by the Exabyte company. Because 8mm technology itself is suitable for large capacity storage, in the early days of less computer data, its application is not very wide, mainly with large and medium-sized computer matching. With the exponential growth of the amount of data in the computer network, 8mm technology is becoming more and more important, which is supported by the rapid growth of 8mm product shipments in recent years. 8mm technology has a broad space for upward development. And, each new, high-end 8mm products, are backward-compatible low-end products, protect the user's original investment.

The future of new tape storage technology Ltolto (Linear Tape open-Linear Tape Open Protocol) technology is a combination of linear multi-channel two-way tape format of the new tape storage technology, its advantage is the service system, hardware data compression, optimize the track surface, High-efficiency error correction technology and improve the performance of tape capacity, such as integrated. Because LTO technology is an "open format" technology, this means that users will be able to have a number of products and a variety of storage media, especially open to bring more innovative innovation, reduce the risk of new technology development, so that the price of products and users benefit from the goal, in addition to improve product compatibility and continuity. LTO fourth generation standard capacity of 800G, transmission speed of 80mb/s~160mb/s, which is currently any type of tape machine can not match. The main reasons for developing LTO are as follows: one is to establish an open tape drive product standard; the other is to continuously improve the reliability of the tape drive products; third, to enhance the scalability of the product to adapt to the real demand for data surges; four is to reduce backup time and improve product performance.

Currently, LTO technology has two storage formats, namely, high-speed open tape format Ultrium and fast access to open Tape format accelis, which can meet the requirements of different users for the LTO storage system, where Ultrium tape format, in addition to the highly reliable LTO technology, It also features large capacity, both individually and in an automated operating environment that is ideal for backup, storage, and archiving applications. The Accelis tape format focuses on fast data storage, Accelis tape formats are well suited for automated operating environments, and can handle a wide range of online data and recovery applications.

Backup software technology backup software technology is very important in the entire data storage backup process, because it is not only related to whether to support the various advanced features of tape, but also to a large extent determine the efficiency of backup. Some people think that the best backup software is the backup function provided by the operating system, such as Unix Tar/cpio, WindowsNT windowsbackup, NetWare sbackup and so on. In fact, because these operating systems can only provide some basic backup functions, the lack of professional backup software high speed and high performance, the current more popular professional backup software is the ARCserve2000 of CA, Veritas's Backupexce and Legato's Networker. As you know, the tape drive on the speed of data transmission has a certain requirement, if the data transmission rate is low, the tape drive can not run continuously. However, professional backup software can automatically transmit data with higher transmission rate by optimizing the data transmission rate, which not only shortens backup time, improves data storage backup speed, but also benefits the tape drive equipment itself. In addition, professional backup software supports new tape drive technology, such as HP's Tapealert technology, which is supported by almost all major professional backup software.

Das, Nas, and SAN storage mode Das (direct attached storage-directly attached storage) refers to connecting a storage device directly to a computer through a SCSI interface or Fibre Channel. The DAS Environment is: 1 The server is geographically dispersed, it is very difficult to interconnect between them via San or NAS (a typical example is the branch of a store or bank); 2 The storage system must be connected directly to the application server (such as Microsoft Cluster Server or some database uses the "raw Partition"), 3, including many database applications and application server applications, they need to connect directly to the storage, groupware applications and some mail services are included.

Direct-attached storage is a good solution, perhaps even the only solution, when the servers are geographically dispersed and difficult to interconnect over remote connections. Another reason to take advantage of direct-attached storage may also be that the enterprise decides to keep the network systems that are not very high in transmission rates.

The emergence of Nas and San responds to three important trends: the network is becoming a major information processing model, the amount of data needed to be stored is increasing, and the importance of data as a strategic asset to gain a competitive advantage.

NAS (Network attached storage-network-attached storage) connects a storage device to a group of computers through a standard network topology, such as Ethernet. NAS is a part-level storage approach that focuses on helping teams and departmental organizations address the need to rapidly increase storage capacity. An engineering team that needs to share large CAD documents is a typical example.

NAS products include memory components (such as hard disk drive arrays, CD or DVD drives, tape drives, or removable storage media) and integrated simple servers that enable you to implement all the features involved in file access and management. Simple servers are optimized to perform a range of simplified functions, such as document storage and services, e-mail, Internet caching, and so on. A simple server integrated in a NAS device separates the functionality related to storage from the other features performed by the application server.

This approach improves the availability of data in two ways. First, even if the corresponding application server is no longer working, the data can still be read. Second, the simple server itself will not crash because it avoids the primary cause of the server crash, which is the problem with the application software.

NAS products have several notable advantages. First, NAS products are truly Plug and play products. NAS devices typically support multiple computer platforms, where users can access the same documents through network support protocols, so NAS devices can be used in mixed unix/windowsnt LANs without modification. Second, the physical location of the NAS devices is also flexible. They can be placed in workgroups, near the application servers in the data center, or in other locations, connected to the network through physical links. Without application server intervention, NAS devices allow users to access data on the network, which reduces CPU overhead and significantly improves network performance.

NAS does not address one of the key issues associated with file servers, that is, bandwidth consumption during backup. Unlike a storage area network (SAN) that transfers backup data streams from a LAN, NAS still uses the network for backup and recovery. One drawback of NAS is that it shifts storage transactions from parallel SCSI connections to the network. This means that a LAN must handle a storage disk request that includes a backup operation, in addition to the normal end user transport flow.

The SAN (storage area network) is connected to a group of computers via Fibre Channel. Multiple host connections are provided in this network, but not through a standard network topology.

Sans Focus on enterprise-class storage-specific issues. The two root causes of problems with current enterprise storage scenarios are the structural constraints that result from the close integration of data and application systems, and the current limitations of small computer system interface (SCSI) standards. Most analysis considers Sans to be future enterprise-class storage scenarios because sans are easy to integrate, improve data availability and network performance, and reduce management jobs.

The advantages of SAN solutions are as follows:

Sans provide an easy way to connect to existing LANs and support widely used SCSI and IP protocols through the same physical channel. Sans are not subject to the current mainstream, SCSI storage-architecture-based layout restrictions. It is particularly important that, with the explosive growth of storage capacity, sans allow enterprises to increase their storage capacity independently.

The structure of the San allows any server to connect to any storage array, so that regardless of where the data is placed, the server can access the required data directly. Because of the fibre interface, the SAN also has a higher bandwidth.

Because San solutions are stripped out of storage functionality from basic functionality, running backup operations eliminates the need to consider their impact on overall network performance. San scenarios also simplify management and centralized control, especially when all storage devices are clustered together. Finally, the fibre-optic interface provides a 10-kilometer connection length that makes it easy to achieve physically separate storage that is not in the computer room.

Sans are primarily used for large storage environments, such as ISPs, banks, etc., but now the San market is affected by issues such as low demand, high cost, and the standard has not yet been determined, but with the increase in the volume of these users, San also has a wide range of application prospects.