How-to
Troubleshoot common PBS errors fast.
Quick checks to clear fingerprint/auth issues, data errors, and performance bottlenecks before they impact backups.
Steps
- Fingerprint or cert errors. Re-fetch and approve the correct TLS fingerprint; ensure time sync and valid cert chain.
- Auth or permission denied. Confirm user/token scope to the datastore/namespace; rotate credentials if in doubt.
- Data/chunk errors. Re-run the backup; if persistent, re-backup the affected guest. Check storage health (ZFS, SMART).
- Performance slowdowns. Reduce concurrency, check I/O latency, and avoid overlapping heavy jobs.
- Network issues. Test connectivity and MTU; ensure firewall rules allow PBS ports from Proxmox VE nodes.
- Review logs. Inspect PBS and PVE logs for error codes; correlate with job IDs and timestamps.
Prereqs
- Access to PBS/PVE logs
- Valid credentials and fingerprint
- Monitoring for storage and network
Quick checks
- Jobs run without auth or fingerprint prompts.
- No new chunk errors appear.
- Throughput back to normal ranges.
- Network/firewall confirms expected paths open.
If something fails
- Rotate tokens; re-approve fingerprint.
- Re-run backups after data errors.
- Lower concurrency and avoid overlapping heavy jobs.
- Check storage health (ZFS status, SMART) and network MTU.
Related guides
Official docs
Proxmox troubleshooting references: PBS troubleshooting guide.
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