SMR HDD (Shingled Magnetic Recording HDD)

A type of hard disk drive that increases storage capacity by overlapping data tracks on the platter, similar to shingles on a roof. This differs from Conventional Magnetic Recording (CMR), where tracks are written side-by-side.

Areal Density

The amount of data that can be stored in a given area on a disk platter. SMR technology boosts areal density by allowing for narrower, overlapping tracks, enabling higher-capacity, cost-effective drives.

Write Performance

A key characteristic affected by SMR. Overlapping tracks means writing data requires rewriting adjacent tracks to avoid overwriting. This can cause significantly slower write speeds, especially for random, non-sequential data.

Write Amplification

A phenomenon where a single logical write operation from the host system triggers multiple physical write operations on the disk. This occurs in SMR drives due to the need to read, modify, and rewrite entire, larger blocks of data.

Host-Managed SMR

An SMR variant where the host system (e.g., the operating system) is explicitly aware of the drive's SMR nature and manages data placement to optimize performance, avoiding the write penalty. Primarily used in data centers.

Drive-Managed SMR

The most common consumer-grade SMR type. The drive itself contains a translation layer that hides the SMR complexity from the host, presenting the drive as a conventional CMR device. This simplifies use but can lead to unpredictable performance slowdowns.

Tag：HDD