RAID is Redundant Array of Independent disk.support "short for Redundant Disk Array technology was born in 1987, by the university of California, Berkeley put forward. With a simple explanation, which will N Taiwan hard disk Controller (points by RAID Hardware, Software) combine into a virtual single big large-capacity hard disk usage. RAID of adopted for storage system (or server built-in memory) bring huge benefits, including improving transmission rate and provide fault-tolerant function is the biggest advantage.
introduction
Its characteristic is N Taiwan hard disk both read faster and Fault Tolerant provides fault-tolerance, so the RAID is as mainly access the data Storage speed (Storage) not separate the Backup.
Say simply, RAID is a chunks independent hard disk (the physical hard disk) according to the different ways of combined form a hard disk group (logical disk), providing higher than single disk storage properties and provide the data backup technique. Composed of disk array of different ways called RAID Levels.
Disk Array in view of different applications use different technology, known as RAID Array Redundant level, RAID is the abbreviation of Disks of simultaneously, and each level represents a kind of technology, now industry of accepted standards is RAID 0 ~ RAID 5. This does not mean technology level of height, level 5 is not superior level 3, level 1 also not lower than level 4, the choice that a RAID level products, pure depending on the user's operating and to apply and decide, and level of discretion no causal relation.
In the RAID a basic concept called Data Availability and replacement EDAP (Protection), its emphasis on the expansion of fault-tolerant mechanism, but also houses, such as: Mylex manufacturer IBM, HP, Compaq, Infortrend Adaptec, such as the key, including the appeal without downtime circumstances can handle the following actions:
RAID disk array support automatic detection fault hard disk,
RAID disk array support reconstruction hard disk bad rail information;
RAID disk array support support not stop the hard disk redundant Hot Spare;
RAID disk array support support not stop the hard disk replacement of a Hot,
RAID disk array support expansion hard disk volume etc.
function
1, expanded by multiple disk storage capacity can be composed capacity huge storage space.
2, reduced the cost of unit volume on the market the maximum capacity of the hard disk per Megabyte capacity price substantially above affordable, so use several affordable disk array of his unit composed of hard disk at a much lower price.
3, improves the speed of a single disk storage the speed of are subject to various periods of technical conditions, to further is often very difficult, and use RAID, can let more hard disk also share data read or write operation, so overall speed have multiplied.
4, reliability RAID system can use two groups of hard disk storage, mirror synchronism finish such safety measures for web server was probably the most important however.
5 and fault-tolerance RAID controller is a key function is fault-tolerant processing. Fault-tolerant array if any single block hard disk errors, will not affect the overall continue to use, senior RAID controller has save data function.
6, for IDE RAID for, there is still a function is the support ATA / 66/100. RAID also is divided SCSI RAID and IDE RAID two kinds, of course IDE RAID to cheap. If the host motherboard does not support ATA / 66/100 hard disk, through the RAID card can be used on a new disk ATA / 66/100 function.
advantages
RAID of adopted for storage system (or server built-in memory) bring huge benefits, including improving transmission rate and provide fault-tolerant function is the biggest advantage.
RAID through use several disk and improve the transmission rate. RAID in multiple disk by simultaneously storage and read data to dramatically increase storage system data Throughput (Throughput). In the RAID, can let a lot of disk drives simultaneously transmit data, and these disk drive in logic is a disk drive, so use RAID can achieve a single disk drives a few times, a few times even hundreds of rate. This is also the RAID originally want to solve the problem. Because at that time CPU speed increases rapidly, and the disk drive data transfer rate cannot be greatly enhanced, and therefore need a scheme to solve the contradiction between the two. RAID finally succeeded.
Through data validation, RAID can provide fault-tolerant function. This is to use RAID the second reason, because the average disk drives cannot provide fault-tolerant function, if not including writing on disk of cyclic redundancy check (CRC) code words. RAID fault-tolerant is built on each disk drive on the hardware fault-tolerant function, so it provides higher security. In many RAID mode has a complete set of mutual calibration/recovery measures, even is the direct mutual mirror backup, which greatly improve the RAID system of forgiveness, improved the system stable redundancy.
Types and application
Based on the different structure, RAID species can divide again: software, hardware, RAID RAID External RAID
Software RAID many cases already contained in the system of, and become one of the function, such as Windows, Netware and Linux. All the operating software RAID by the central processor is responsible, so the system resources utilization will be high, thus reducing the performance of the system. Software RAID is not need additionally add any hardware device, because it is by your system -- primarily is CPU function - provide all the ready-made resources.
Hardware RAID is usually a PCI CARDS, in this card will be processors and memory. Because this card processors have can provide all the resources needed to RAID, so it won't take up system resources, to make the system's performance can be enhanced greatly. The application of the hardware RAID is one can connect built-in hard disk, hot swaps buoy or external storage devices. No matter how hard disk, connection control are in the RAID on the card, which is controlled by the system. In the system, hardware RAID PCI cartoon often need Ann driver, otherwise system will refuse to support. Disk array can be in installation system before or after produce, the system will be regarded as a (large) hard drive, and it has the function of fault tolerant and redundancy. Disk array not only can join a ready-made system, it can more support capacity expansion. Method is also very simple, need only to join a new hard disk and perform some simple commands, the system can real-time using this new added capacity.
External extended RAID also is to belong to a hardware RAID, difference lies in the RAID card not to install the system installed outside, but inside buy a storage device. But the external storage equipment will be connected to the system of SCSI CARDS. System without any RAID functions, because it only a SCSI CARDS, All the RAID functions will have moved to the external storage. Benefit is external storage can often connect more hard disk, not be system affected by the size of the box. And some advanced technologies, such as double-machine fault-tolerant, it is need multiple servers outside connected to an external storage, to provide tolerance. The application of external extended RAID is one can install any operation system, therefore is operating system and irrelevant. Because in the system exists only a SCSI CARDS, not RAID card. And for this system and this piece of SCSI CARDS for, the external extended the RAID is just a large disk, not any special equipment, so the external extended the RAID can install any of the operating system. The only requirement is that zhang SCSI CARDS in this operating system to install the driver.
RAID is Redundant Array of Independent disk.support "short for Redundant Disk Array technology was born in 1987, by the university of California, Berkeley put forward. With a simple explanation, which will N Taiwan hard disk Controller (points by RAID Hardware, Software) combine into a virtual single big large-capacity hard disk usage. RAID of adopted for storage system (or server built-in memory) bring huge benefits, including improving transmission rate and provide fault-tolerant function is the biggest advantage.introductionRAID Redundant Array of disk Array (Independent Disks)Its characteristic is N Taiwan hard disk both read faster and Fault Tolerant provides fault-tolerance, so the RAID is as mainly access the data Storage speed (Storage) not separate the Backup.Say simply, RAID is a chunks independent hard disk (the physical hard disk) according to the different ways of combined form a hard disk group (logical disk), providing higher than single disk storage properties and provide the data backup technique. Composed of disk array of different ways called RAID Levels.Disk Array in view of different applications use different technology, known as RAID Array Redundant level, RAID is the abbreviation of Disks of simultaneously, and each level represents a kind of technology, now industry of accepted standards is RAID 0 ~ RAID 5. This does not mean technology level of height, level 5 is not superior level 3, level 1 also not lower than level 4, the choice that a RAID level products, pure depending on the user's operating and to apply and decide, and level of discretion no causal relation.In the RAID a basic concept called Data Availability and replacement EDAP (Protection), its emphasis on the expansion of fault-tolerant mechanism, but also houses, such as: Mylex manufacturer IBM, HP, Compaq, Infortrend Adaptec, such as the key, including the appeal without downtime circumstances can handle the following actions:RAID disk array support automatic detection fault hard disk,RAID disk array support reconstruction hard disk bad rail information;RAID disk array support support not stop the hard disk redundant Hot Spare;RAID disk array support support not stop the hard disk replacement of a Hot,RAID disk array support expansion hard disk volume etc.function1, expanded by multiple disk storage capacity can be composed capacity huge storage space.2, reduced the cost of unit volume on the market the maximum capacity of the hard disk per Megabyte capacity price substantially above affordable, so use several affordable disk array of his unit composed of hard disk at a much lower price.3, improves the speed of a single disk storage the speed of are subject to various periods of technical conditions, to further is often very difficult, and use RAID, can let more hard disk also share data read or write operation, so overall speed have multiplied.4, reliability RAID system can use two groups of hard disk storage, mirror synchronism finish such safety measures for web server was probably the most important however.5 and fault-tolerance RAID controller is a key function is fault-tolerant processing. Fault-tolerant array if any single block hard disk errors, will not affect the overall continue to use, senior RAID controller has save data function.6, for IDE RAID for, there is still a function is the support ATA / 66/100. RAID also is divided SCSI RAID and IDE RAID two kinds, of course IDE RAID to cheap. If the host motherboard does not support ATA / 66/100 hard disk, through the RAID card can be used on a new disk ATA / 66/100 function.advantagesRAID of adopted for storage system (or server built-in memory) bring huge benefits, including improving transmission rate and provide fault-tolerant function is the biggest advantage.RAID through use several disk and improve the transmission rate. RAID in multiple disk by simultaneously storage and read data to dramatically increase storage system data Throughput (Throughput). In the RAID, can let a lot of disk drives simultaneously transmit data, and these disk drive in logic is a disk drive, so use RAID can achieve a single disk drives a few times, a few times even hundreds of rate. This is also the RAID originally want to solve the problem. Because at that time CPU speed increases rapidly, and the disk drive data transfer rate cannot be greatly enhanced, and therefore need a scheme to solve the contradiction between the two. RAID finally succeeded.Through data validation, RAID can provide fault-tolerant function. This is to use RAID the second reason, because the average disk drives cannot provide fault-tolerant function, if not including writing on disk of cyclic redundancy check (CRC) code words. RAID fault-tolerant is built on each disk drive on the hardware fault-tolerant function, so it provides higher security. In many RAID mode has a complete set of mutual calibration/recovery measures, even is the direct mutual mirror backup, which greatly improve the RAID system of forgiveness, improved the system stable redundancy.Types and applicationBased on the different structure, RAID species can divide again: software, hardware, RAID RAID External RAIDSoftware RAID many cases already contained in the system of, and become one of the function, such as Windows, Netware and Linux. All the operating software RAID by the central processor is responsible, so the system resources utilization will be high, thus reducing the performance of the system. Software RAID is not need additionally add any hardware device, because it is by your system -- primarily is CPU function - provide all the ready-made resources.Hardware RAID is usually a PCI CARDS, in this card will be processors and memory. Because this card processors have can provide all the resources needed to RAID, so it won't take up system resources, to make the system's performance can be enhanced greatly. The application of the hardware RAID is one can connect built-in hard disk, hot swaps buoy or external storage devices. No matter how hard disk, connection control are in the RAID on the card, which is controlled by the system. In the system, hardware RAID PCI cartoon often need Ann driver, otherwise system will refuse to support. Disk array can be in installation system before or after produce, the system will be regarded as a (large) hard drive, and it has the function of fault tolerant and redundancy. Disk array not only can join a ready-made system, it can more support capacity expansion. Method is also very simple, need only to join a new hard disk and perform some simple commands, the system can real-time using this new added capacity.External extended RAID also is to belong to a hardware RAID, difference lies in the RAID card not to install the system installed outside, but inside buy a storage device. But the external storage equipment will be connected to the system of SCSI CARDS. System without any RAID functions, because it only a SCSI CARDS, All the RAID functions will have moved to the external storage. Benefit is external storage can often connect more hard disk, not be system affected by the size of the box. And some advanced technologies, such as double-machine fault-tolerant, it is need multiple servers outside connected to an external storage, to provide tolerance. The application of external extended RAID is one can install any operation system, therefore is operating system and irrelevant. Because in the system exists only a SCSI CARDS, not RAID card. And for this system and this piece of SCSI CARDS for, the external extended the RAID is just a large disk, not any special equipment, so the external extended the RAID can install any of the operating system. The only requirement is that zhang SCSI CARDS in this operating system to install the driver.
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