archive_command

What archive_command Does

archive_command is the shell command PostgreSQL executes when a WAL segment is ready to be archived.

It receives placeholders for source path and WAL filename and must return success only when durable copy is complete.

A weak command script creates invisible recovery risk even if backups look healthy.

Reliability Requirements

• Idempotent behavior for retries
• Strict non-zero exit on failure
• Durable destination and permission checks
• Observability for failures and latency

Operational Pitfalls

Commands that suppress errors, write to unstable destinations, or skip integrity checks can break your WAL chain.

Treat archive_command as a critical production pipeline, not a one-time setup.

• No silent ignore of failed copy operations
• No best-effort local-only targets
• No unmonitored script drift after infra changes

Related Recovery Path

archive_command writes WAL out; restore_command reads it back during recovery.

Both ends must be tested together in drills to validate actual PITR readiness.