What is this folder, and why do I get telemetry stored for months?

hi, telemetry can be disabled via config:

telemetry.enabled=false

the config change takes effect after restart. after telemetry is disabled the telemetry data folders (sys.telemetry_wal, telemetry) can be deleted. alternatively you can keep telemetry enabled but keep only recent data by removing older partitions. telemetry info can be useful when troubleshooting certain issues, such as performance problems.

Thanks, Telemetry takes 10% of storage, so IMHO telemetry should be disabled by default.

there are pros and cons. i think this has come up in the past already, and probably the best would be to impose limits (max time and/or storage), and keep only the latest telemetry data.