Introduction to RAID 2.0+

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Hello, everyone!

The post will share with you what is RAID 2.0+.

Origin of the RAID technology

The term Redundant Array of Independent Disks (RAID) was first defined by the University of California, Berkeley in 1987. The basic idea of RAID is to combine multiple independent physical disks based on a certain algorithm to form a virtual logical disk that provides a larger capacity, higher performance, and better data error tolerance. This technology bred the external storage market.

Development of storage virtualization technologies

What is RAID 2.0+?

RAID 2.0+ employs the two-layer virtualization management mode rather than the traditional management mode. In addition to underlying disk management, RAID 2.0+ uses the Smart series software to efficiently manage upper-layer resources.

How Does RAID 2.0+ Work?

Huawei RAID 2.0+ key concepts: 

Chunk (CK)

Each CK is 64 MB physical space divided from disk space in a storage pool. CK is the basic unit of a RAID group.

Disk Group

A disk group(DG) is a set of disks of the same type in a disk domain. The disk type can be SSD, SAS, or NL-SAS.

Logical Drive

A logical drive(LD) is a disk that is managed by a storage system and corresponds to a physical disk.

Chunk Group

A chunk group (CKG) is a logical storage unit that consists of CKs from different disks in the same DG based on the RAID algorithm. lt is the minimum unit forallocating resources from a disk domain to a storage pool.

Extent

Each CKG is divided into logical storage spaces of fixed and adjustable size called extents. Extent is the minimum unit (granularity) for migration and statistics of hot data. lt is also the minimum unit for space application and release in a storage pool.

Grain

When a thin LUN is created, extents are divided into blocks of a fixed size, called grains. A thin LUN allocates storage space by grains. Logical block addresses (LBAs) in grain are consecutive.

Volume and LUN

Avolume is an internal management object in a storage System.

ALUNiis a storage unit that can be directly mapped to a host for data reads and writes. ALUN is the external embodiment of a volume.

Simplified storage planning

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