smartctl (SMART control) — Disk SMART health checks

Linux / File and disk management / smartctl.html

A tool that reads SMART attributes and self-test results to detect early disk failures.

Basic Information

What is this command?

smartctl reads the SMART values a disk records itself and reports reallocated sectors, pending sectors, temperature and power-on hours. It supports both HDDs and NVMe SSDs.

Checking -H and -a regularly helps you replace a disk before a sudden failure. NVMe devices need the -d nvme option.

What problems does it solve?

• You want early warning of a failing disk
• You are reviewing disk temperature and power-on hours
• You want to run and record a self-test
• You need to decide which disk to replace

Key features

Health summary

-H prints a short PASSED or FAILED verdict.

• When to use: You need a quick verdict
• What you get: The disk's own verdict
• Limitations: PASSED does not reveal a worsening individual attribute.

Full attribute view

-a shows the attribute table, error log and self-test history.

• When to use: You need detailed diagnostics
• What you get: Reallocated and pending sectors, temperature, error log
• Limitations: Attribute names differ slightly between vendors.

Run a self-test

-t short or -t long starts an internal self-test.

• When to use: Your maintenance routine includes a diagnostic
• What you get: Test progress and result log
• Limitations: A long test takes hours and adds load.

Installation and usage

Check whether it is installed

smartctl --version

sudo apt install smartmontools # Debian/Ubuntu sudo dnf install smartmontools # Fedora

Real-world examples

Check health

Show only the SMART verdict.

sudo smartctl -H /dev/sda

Attributes and error log

Print attributes and recent error records.

sudo smartctl -a /dev/sda

Short self-test

Start a short test and read the result from the log.

sudo smartctl -t short /dev/sda
sudo smartctl -l selftest /dev/sda