Glossary / NAS

RAID 1

RAID 1 mirrors data across two drives, so one drive can fail without immediately making the data unavailable. It reduces usable capacity and is not a substitute for a backup.

What RAID 1 means

RAID 1 is a storage arrangement that mirrors the same data on two drives. If one drive fails, the other may still hold an accessible copy, depending on the product's implementation and current system state.

On NASFit, RAID 1 appears as an option in the storage drive controller specification. The catalog context shows RAID 1 alongside Standard, JBoD, and RAID 0 on published products.

Why it matters

RAID 1 is mainly about redundancy. It can reduce the risk of immediate data unavailability from a single drive failure, which may matter when a NAS stores files that need to remain accessible.

The trade-off is capacity: a mirrored pair generally provides usable capacity comparable to one drive rather than the combined capacity of both. RAID 1 also does not protect against accidental deletion, malware, file corruption, theft, or damage affecting the whole device. Keep a separate backup for those risks.

When the label matters—and when it does not

RAID 1 matters when you are comparing products that may use two drives and you want a mirrored storage option. It is less relevant if you plan to use a single drive, need the combined capacity of multiple drives, or will manage redundancy through another system.

A RAID 1 label is a capability flag, not a quality rating. It does not by itself show how quickly a rebuild completes, how the product reports a failed drive, whether drives can be replaced while operating, or how the system behaves during a failure. Those details remain unknown unless the product page or manufacturer documentation states them.

What to check on a product page

Look for:

The number of drive bays and the drives supported by the product
Whether RAID 1 is listed as an available mode or only mentioned in general documentation
The usable capacity shown when two drives are installed
Drive-failure alerts, replacement procedures, and rebuild information
Whether the product distinguishes RAID support from backup features
Any stated limits on drive size, drive type, or mixing drives

A product listing that says “RAID 1” does not establish every detail of its implementation or compatibility. Confirm those points before treating the label as a complete specification.

Nearby terms

RAID 0 combines storage across drives for capacity and performance, but it does not mirror data. JBoD presents drives independently rather than creating a mirrored set. Standard may indicate a non-RAID controller mode, but the exact behavior depends on the product documentation.