Postfix Performance Tuning
Tune concurrency and process limits based on measured bottlenecks.
Production note: Back up configuration, run
postfix check, and stage changes before reloading.Measure first
Capture queue age, destination deferrals, CPU, memory, disk latency, DNS latency, and process utilization before changing limits.
Relevant parameters
default_process_limit = 100
smtp_destination_concurrency_limit = 20
smtp_destination_recipient_limit = 50
qmgr_message_active_limit = 20000Storage
Queue performance depends on filesystem latency and inode behavior. Avoid unsafe blanket tuning.
Provider behavior
Remote-provider throttling is not solved by increasing concurrency. Segment and tune based on SMTP responses.