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Systems & Data Center · Foundational

RAID 1

Disk mirroring, writing identical data to two drives so the array survives one drive failure.

Definition

Usable capacity is that of a single drive (50 percent efficiency). Reads can be serviced by either drive, and there is no parity calculation overhead. It is common for OS boot volumes.

Example

Two 960 GB SSDs in RAID 1 hold the hypervisor boot volume.

Exam tip

RAID 1 needs a minimum of two drives and yields 50 percent usable capacity.

Don't confuse it with

Related terms