RAID disk Array notes

Disk array raid is an essential knowledge of server maintenance and has previously been less concerned with server maintenance knowledge. Currently responsible for the maintenance of several servers in the computer room, so pay attention to this aspect of the content.

Disk arrays are made up of several separate disks, providing two aspects: Data security redundancy and improved performance.

1, security redundancy: through redundant data storage, when a disk failure in the array, the replacement can restore the data to a full state.

2, Improve performance: the data block storage on different disk, can realize parallel reading and writing, thus improving the read and write performance of the storage device.

RAID disk arrays have a variety of structures, each biased.

RAID0: Data is stored on multiple disks with no redundant storage. Features, fast speed. Can only be used when the data security requirements are not high.

RAID1: Data Mirroring. The data security of RAID 1 is best at all RAID levels. But its disk utilization is only 50%, the lowest of all RAID levels.
RAID2:RAID3:RAID4:RAID5: The structure with check code, read and write performance and utilization ratio is higher than RAID1.

RAID0+1:RAID10: Consists of a raid0+raid1 two-layer structure, the latter having only one complete controller.

Common servers use RAID1 and RAID5 more.

In the event of a disk failure in a hardware RAID array, the RAID array control hardware proactively recovers data by simply replacing the faulty disk without rebooting the system.

RAID disk Array notes