Home Assistant database growing and SD card wearing out: tune the recorder

What the recorder does

Every state change and event goes into the recorder database. That's SQLite, home-assistant_v2.db in the config directory, unless you configure another database. Defaults:

Home Assistant's own docs warn that the write load can hurt responsiveness and the life of the storage medium (SD card).

Symptoms

• Database file of several GB, slow history graphs, long backups.
• Sluggish UI on a Raspberry Pi; SD card failures after months.

Fix

Exclude what you never look at: power meters updating every second, signal strength, uptime counters, "last seen" sensors.

recorder:
  purge_keep_days: 10
  commit_interval: 30        # fewer, larger writes
  exclude:
    entity_globs:
      - sensor.*_signal_strength
      - sensor.*_uptime
    entities:
      - sensor.power_meter_raw

• Excluded entities no longer have history. Long-term statistics (the energy dashboard, statistics graphs) are separate, so check what you still need.
• Raising commit_interval means the last seconds of data can be lost on a crash; that's usually acceptable.
• Old data only disappears after a purge. Run the recorder.purge action once after changing exclusions if you want space back sooner.

Storage

On a Raspberry Pi, move Home Assistant to an SSD instead of an SD card (see the Raspberry Pi SD-card corruption item). A good power supply matters just as much.