PowerMTA monitors directories for new .msg files. Ensure permissions are locked:
chown pmta:pmta /var/spool/pmta/pickup
chmod 750 /var/spool/pmta/pickup
Based on real-world deployments (Dell R630, 16 cores, 64GB RAM, SSD storage): powermta 60r3
| Metric | PowerMTA 60r3 Performance | |--------|----------------------------| | Injection (messages/second) | 15,000 - 25,000 | | Outbound delivery (mixed domains) | 250,000 - 500,000 per hour | | Concurrent SMTP connections | 65,000 (requires kernel tuning) | | Queue size (spool) | 10 million messages before performance degradation | | Memory usage (idle) | ~600MB | | Memory usage (full load) | 4GB - 8GB | PowerMTA monitors directories for new
Verdict: PowerMTA 60r3 is a workhorse. One properly tuned instance can replace an entire cluster of Postfix servers. Based on real-world deployments (Dell R630, 16 cores,
PowerMTA 60r3’s DSN parser is legendary. Define categories:
<dsn-rule 550_5.1.1> pattern "550 5.1.1.*User unknown" category hard-bounce action reject </dsn-rule>
<dsn-rule 450_4.2.2> pattern "450 4.2.2.*Mailbox full" category soft-bounce action requeue retry-interval 3600 </dsn-rule>