红帽全球峰会第 16 章 Managing RAID
You can use a Redundant Array of Independent Disks (RAID) to store data across multiple drives. It can help to avoid data loss if a drive has failed.
16.1. Overview of RAID
In a RAID, multiple drives (HDD, SSD, or NVMe) are merged into an array to achieve performance or redundancy beyond what a single expensive drive can offer. This array appears to your system as one logical storage unit.
RAID supports various configurations, including levels 0, 1, 4, 5, 6, 10, and linear. RAID uses techniques such as disk striping (RAID Level 0), disk mirroring (RAID Level 1), and disk striping with parity (RAID Levels 4, 5 and 6) to achieve redundancy, lower latency, increased bandwidth, and maximized ability to recover from hard disk crashes.
RAID distributes data across each device in the array by breaking it down into consistently-sized chunks, commonly 256 KB or 512 KB, although other values are acceptable. It writes these chunks to a hard drive in the RAID array according to the RAID level employed. While reading the data, the process is reversed, giving the illusion that the multiple devices in the array are actually one large drive.
RAID technology is beneficial for those who manage large amounts of data. The following are the primary reasons to deploy RAID:
- It enhances speed
- It increases storage capacity using a single virtual disk
- It minimizes data loss from disk failure
- The RAID layout and level online conversion
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