Cal Corum 6c8d199359 Add Pi-hole HA documentation and networking updates

Add dual Pi-hole high availability setup guide, deployment notes, and
disk optimization docs. Update NPM + Pi-hole sync script and docs.
Add UniFi DNS firewall troubleshooting and networking scripts CONTEXT.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

2026-02-07 22:19:56 -06:00

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Pi-hole Disk Optimization - 2026-02-06

Problem

Primary Pi-hole (npm-pihole at 10.10.0.16) had critical disk space issues:

Root filesystem: 91% full (27GB used of 31GB)
Pi-hole data: 3.6GB total
- pihole-FTL.db: 2.8GB (query log database)
- gravity.db: 460MB (blocklist database)
- gravity.db.v5.backup: 114MB (old v5 backup)
Query retention: 91 days (default)
Total queries stored: 26.4 million

Actions Taken

1. Removed Old Backup Database

rm /home/cal/container-data/pihole/etc-pihole/gravity.db.v5.backup

Space freed: 114MB

2. Cleaned Up Docker Resources

docker system prune -af --volumes

Space freed: 4.3GB

Removed unused images (old Pi-hole versions, Jellyfin, Foundry, etc.)
Removed stopped containers
Removed unused networks

3. Reduced Query Log Retention

echo "database.maxDBdays=7.0" >> /etc/pihole/pihole-FTL.conf
docker compose restart

Configuration: Changed from 91 days to 7 days Future savings: Database will automatically maintain ~7 days of logs instead of 91

Results

Metric	Before	After	Improvement
Disk Usage	91% (27GB/31GB)	73% (22GB/31GB)	-18%
Free Space	2.8GB	8.2GB	+5.4GB
Total Freed	-	4.3GB	-

Ongoing Maintenance

Automatic Cleanup

Pi-hole will now automatically:

Delete queries older than 7 days
Maintain FTL database size around ~300-500MB (instead of 2.8GB)
Keep the most recent week of query logs for troubleshooting

Manual Cleanup (if needed)

# Flush Pi-hole logs
docker exec pihole pihole -f

# Check disk usage
df -h /
du -sh /home/cal/container-data/pihole/etc-pihole/*

# Clean unused Docker resources
docker system prune -af --volumes

# Check query count
docker exec pihole pihole-FTL sqlite3 /etc/pihole/pihole-FTL.db 'SELECT COUNT(*) FROM queries;'

Monitoring Recommendations

Set up disk space alerts when usage exceeds 85%:

# Add to cron (daily check)
0 8 * * * df -h / | awk '$5+0 > 85 {print "Warning: Disk usage at " $5 " on npm-pihole"}' | mail -s "Disk Alert" admin@example.com

Check Pi-hole database size monthly:

du -h /home/cal/container-data/pihole/etc-pihole/pihole-FTL.db

Configuration File

/etc/pihole/pihole-FTL.conf:

database.maxDBdays=7.0  # Keep queries for 7 days only

Prevention Tips

Regular Docker cleanup: Run docker system prune monthly
Monitor disk usage: Check df -h weekly
Review query retention: 7 days is sufficient for most troubleshooting
Consider disabling query logging if not needed:
```
pihole logging off
```
Archive old logs before major upgrades (like v5→v6)

Space Budget Estimates

With 7-day retention:

Pi-hole FTL database: ~300-500MB (vs 2.8GB before)
Gravity database: ~460MB (36 blocklists)
Docker images: ~2-3GB (active containers only)
System overhead: ~20GB
Recommended free space: 5GB+ for headroom

Current allocation is healthy at 73% with 8.2GB free.

3.1 KiB Raw Blame History