First, explain what a surprise attack is. Surprise. In computer terminology, RAID (Redundant Array of Independent Disks); The basic idea of disk array in Taiwan Province Province is to combine several relatively cheap small disks into a disk group, so that the performance can reach or even exceed that of an expensive disk with huge capacity. Depending on the selected version, RAID has one or more advantages over a single disk: enhanced data integration, enhanced fault tolerance, and increased throughput or capacity. In addition, to a computer, a disk group is like a disk or logical storage unit. It is divided into RAID- 1, RAID- 10, RAID-3, RAID-30, RAID-5 and RAID-50. Simply put, RAID is to combine multiple hard disks into a logical hard disk, so the operating system only regards them as a single hard disk, not multiple different ones. RAID is often used on server computers, and the same hard disks are often used in combination. Due to the declining price of hard disk and the more effective integration of RAID function with motherboard, it has also become the choice of advanced end users, especially for jobs that need a lot of storage, such as video and audio production. The original RAID is divided into different levels, and each level has its theoretical advantages and disadvantages. Over the years, the concept of RAID has different applications. Basic RAID Classification RAID 0 combines multiple disks into a large disk, which has no redundancy, parallel I/O and the fastest speed. RAID 0 is also called striping. It juxtaposes multiple disks into a large disk. When storing data, it segments the data according to the number of disks, and then writes the data to these disks at the same time. So in all levels, RAID 0 is the fastest. However, RAID 0 has no redundancy. If one disk (physically) is damaged, all data will be lost. Theoretically, disks are mostly equal to [single disk performance ]x[ number of disks], but in fact, due to bus I/O bottleneck and other factors, RAID performance will decline with the margin. That is to say, if the performance of one disk is 50MB/ s, the performance of RAID 0 of two disks is about 96MB/ s, and the RAID 0 of three disks may be 130MB/ s instead of 65430 MB/s, so the performance of RAID 0 of two disks can be obviously improved. RAID 1 More than two groups of N disks mirror each other, which does not improve the speed, but allows N- 1 disks to be damaged, with the highest reliability. RAID 1 is a mirror image. The principle is to write the same data into the mirror hard disk and store the data on the main hard disk at the same time. When the main hard disk (physically) is damaged, the mirror hard disk will replace the main hard disk. Because there are mirrored hard disks for data backup, the data security of RAID 1 is the best among all RAID levels. However, no matter how many disks are used in RAID 1, only the capacity of one disk is calculated, which is the lowest level of disk utilization on all RAID. RAID 2 This is an improved version of RAID 0, which encodes data into Hamming code and divides it into bits, and writes the data into hard disks respectively. Because error correction code (ECC) is added to the data, the total capacity of the data will be greater than the original data. RAID 3 adopts byte interleaving technology.
It needs to encode data bits, then divide them into hard disks, and store them in a single hard disk after parity check. However, because the bits in the data are scattered on different hard disks, even if you want to read a small piece of data, you may need all the hard disks to work. Therefore, this specification is more suitable for using RAID 4 when reading a large amount of data. Unlike RAID 3, partitions are stored in blocks on the hard disk. However, every time the data is accessed, the corresponding parity metadata should be taken out from the hard disk checked by the peer for verification. Due to too frequent use, the loss of hard disk may increase. RAID 5 RAID Level 5 is a storage solution that gives consideration to storage performance, data security and storage cost. It uses disk striping technology. RAID5 does not back up the stored data, but stores the data and the corresponding parity information on the disks that make up RAID 5, and the parity information and the corresponding data are stored on different disks. When the disk data of RAID5 is damaged, the damaged data can be recovered by using the remaining data and the corresponding parity information. RAID 5 can be understood as a compromise between RAID 0 and RAID 1. RAID 5 can provide data security for the system, but the degree of security is lower than that of mirroring, and the utilization rate of disk space is higher than that of mirroring. The data reading speed of RAID 5 is similar to that of RAID 0, but with an extra parity information, the data writing speed is slightly slower than that of a single disk. At the same time, because multiple data correspond to one parity information, the disk space utilization rate of RAID 5 is higher than that of RAID 1, and the storage cost is relatively low. RAID 6 allows two hard drives in the same array to fail at the same time (or if one hard drive cannot be replaced, the second hard drive will also fail). When the new hard disk is replaced, the other two ordinary hard disks will create backup data in the new hard disk. Therefore, at least four or more hard disks are required to take effect. RAID 10 is in this array.
Both have the characteristics of 0 and 1.
That is, it has the advantages of mirroring and splitting at the same time.
But you need more hard drives.
At least 4 hard disks are needed to achieve the effect of 0 1, and the raid control card is a hard disk card with all or part of the above raid functions.
Reference: I
zh。 *** /w/index？ RAID & amp variant =zh-
I provide free computer consultation: 02-294058 18. As long as I ~ computer maintenance ~ computer re-irrigation ~ computer problems ~ computer maintenance ~ re-irrigation win7~xp re-irrigation ~ I'll find them. It is convenient for them to work in the government! ! You can contact them to see. Very high evaluation ... you can try it! ! Tel: 02-294058 18 or add line ~ direct online inquiry! ID:gmepc 168 I hope I can help you with Yahoo's service. serviceplus.yahoo/booth/seller/y0 193898792.