Background tasks on day one

Initial library processing

A fresh install processes your existing library in batches: scanning files, reading codecs and tracks, fetching metadata and artwork, and generating recommendation embeddings. Enabled features add intro detection and music audio analysis.

This initial backlog can take minutes to a day or more, depending on library size, hardware, network speed, and provider rate limits. The backlog worker picks up remaining work automatically. Once it catches up, new additions account for most of the load; audio analysis and intro detection repeat only when files change.

Self-generated trickplay is disabled by default because it uses substantial CPU and disk space.

Playback during processing

A scanned file can play before enrichment finishes. Lumastra reads the file’s technical details on demand. Filenames and placeholder artwork may appear until metadata arrives; recommendations and detected skip segments become available as their respective tasks finish.

Failures that need attention

Transient failures, such as provider rate limits or network errors, retry with backoff. Stopped retrying means retries are exhausted: fix the cause, then retry the work.

Auto-pause temporarily quarantines a task after repeated failures. It probes again after a cooldown and resumes if successful. Repeated trips warrant checking the dependency or error in the task’s failure history.

An unidentified title under Library → Fix matches (/admin/library/fix-matches) is a metadata-matching problem. Correct its title, year, or provider match there; rerunning unrelated tasks won’t fix the match.

For a backlog that stops progressing, use Monitoring tasks and pipelines and the troubleshooting recipes.

Reduce background load

• Pause or reschedule a task in Tasks → Overview (/admin/tasks). Pause stops automatic starts but still allows manual runs. For scheduling rules, see task triggers.
• Lower concurrency in Settings → Task runner (/admin/settings/tasks), under Task Runner & Queue Tuning. Per-resource-class caps reduce peak load at the cost of a longer catch-up. Environment overrides are documented as LUMASTRA_CONCURRENCY_* in the environment variable reference.
• Disable optional work in the same page’s Advanced Tasks section. These persistent switches cover selected tasks, including anime cross-reference ID lookups (Fribb and MyAnimeList), local trickplay serving, and library integrity checks.

History and log retention

Settings → Task runner → Advanced Tasks also controls how long task history, admin audit logs, watch history, failure events, quota records and webhook deliveries are kept. Shorter retention reduces database growth and leaves less history for troubleshooting; task history first moves from hot storage to an archive.

For sustained load after the initial backlog clears, see Performance tuning.