RAID 1, mirror disk array. Each disk has a mirror disk, and the contents of the mirror disk are consistent with the original disk at any time. RAID 1 has the highest security, but only half of the disk space is used to store data. It is mainly used in situations where data security is highly required and damaged data can be quickly recovered. This RAID mode requires only 2 disks per group.
RAID0+ 1, as the name implies, combines RAID0 and RAID 1 technologies. Except for data distributed on multiple disks, each disk has its own physical mirror disk, which provides full redundancy, allows less than one disk to fail without affecting data availability, and has fast reading and writing ability. However, RAID0+ 1 requires at least 4 disks to build.
RAID 5, a parity disk array without independent parity disks. Parity is also used to check for errors, but there is no separate parity disk. Instead, a special algorithm is used to calculate the storage location of any stripe check block. This can ensure that any read-write operation of the check block will be balanced in all RAID disks, which not only improves the system reliability but also eliminates the possibility of bottleneck, and has good performance for reading and writing large and small data. In order to write data and check code information on all disks in the array, RAID 5 needs at least three disks, so in this case, the disk capacity of 1/3 will be occupied by the backup check code and cannot be used. When there are four disks, the disk capacity of 1/4 will be needed as a backup to minimize the worst-case rate. When the number of disks increases, the disk capacity occupied by the backup check code on each disk will decrease, but the risk rate of disk failure will also increase. Once you have two disks at the same time, you cannot recover data.
JBOD JBOD (just binding disks) is a simple disk binding. JBOD logically connects several physical disks one by one to provide a large logical disk. The data on JBOD is only stored from the first disk. When the storage space of the first disk runs out, the data is stored from the following disks in turn. The access performance of JBOD is completely equivalent to the access operation on a single disk, and it does not provide data security. It just provides a way to use disk space, and the storage capacity of JBOD is equal to the sum of all the disks that make up JBOD.
Matrix RAID, matrix disk array. It is a patented RAID mode recently created by Intel for SATA interface. Its characteristic is that it can realize RAID 0 and RAID 1 modes on two disks at the same time. Its working principle is to divide part of the disk space of two disks into RAID 0 or 1, and the remaining space consists of RAID 1 or 0. Matrix RAID also has a function: a "hot backup" hard disk that supports RAID 1 array partition. Motherboards that usually support matrix RAID have four SATA interfaces, but only two hard disks and two SATA interfaces are needed to build a set of matrix RAID. The other two free SATA interfaces can be plugged into the hard disk to start the "hot backup" function. When a hard disk in a matrix RAID system fails, the "hot backup" hard disk will immediately take over its work to ensure the data security in the RAID 1 array partition. Because the data in the partition of RAID 0 array has been destroyed when the hard disk crashes, the "hot backup" hard disk is invalid for RAID 0 array.
The above are all the RAID modes that can be supported by the RAID controller installed on the mainstream upgrade motherboard at present. Because the manufacturer and product model of the RAID controller are different, the types of RAID modes that can be supported are also different. Only a few motherboards can fully support the above RAID modes, and the specific types of RAID modes supported by each motherboard can be found in the product introduction of the upgrade official homepage. Other RAID modes are basically used in professional servers and workstations, so I won't introduce them here.
I will teach you step by step how to set up Raid on each motherboard of the disk array.
Use of disk space in RAID mode
According to the size of disk space that can be used by different RAID modes in practical application, the following table is taken as an example:
* Because of its special concept of disk allocation, matrix RAID is illustrated here separately: for example, two disks of 120G are used to form a RAID with a total capacity of 240G. First, a RAID 0 is established, and a RAID 0 disk capacity is manually specified between 1 and 238G. Then use the remaining disk space such as100g (raid 0)+70g (raid1) or 50G (RAID 0)+ 95G(RAID 1). How to allocate the disk sizes of RAID 0 and RAID 1 can be determined according to the use requirements.