# Ignore maxStalenessSeconds if primary is available. --- heartbeatFrequencyMS: 25000 # 25 seconds. topology_description: type: ReplicaSetWithPrimary servers: - &1 address: a:27017 type: RSPrimary avg_rtt_ms: 5 lastUpdateTime: 0 maxWireVersion: 6 lastWrite: {lastWriteDate: {$numberLong: "1"}} - &2 address: b:27017 type: RSSecondary avg_rtt_ms: 5 lastUpdateTime: 0 maxWireVersion: 6 lastWrite: {lastWriteDate: {$numberLong: "1"}} read_preference: mode: PrimaryPreferred maxStalenessSeconds: 150 suitable_servers: - *1 in_latency_window: - *1