Apache Kafka Complete Practice Exam 2026 – All-in-One Prep

The configuration parameter that governs how long a follower can remain inactive before being classified as out of sync is indeed related to the concept of replica lag. The value of this parameter, when exceeded, indicates that the follower is too far behind the leader in terms of data replication, leading the broker to consider it out of sync.

Specifically, replica.lag.time.max.ms defines the maximum time that a follower replica is allowed to be lagging behind the leader before it is considered to be out of sync. When the follower's replication lag exceeds this threshold, it can be deemed unhealthy or unreliable, and Kafka may take actions such as not allowing it to participate in leader elections or potentially even marking it as out of sync.

In contrast, the other parameters relate to different aspects of replica management:

- replica.fetch.wait.max.ms is related to the maximum time a replica will wait to fetch data before giving up on a request.

- replica.session.timeout.ms specifies how long a connection to a broker can be idle before the session is terminated, typically in the context of maintaining a connection to the broker.

- replica.heartbeat.interval.ms refers to the frequency at which a follower sends heartbeats to confirm it is still alive and responding.

Understanding the role of replica