num.recovery.threads.per.data.dir — Kafka Broker Configuration
The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
Description
The number of threads per data directory to be used for log recovery at startup and flushing at shutdown
Default Values by Kafka Version
| Kafka Version | Default Value |
|---|---|
| 0.8.2 | 1 |
| 0.9.0 | 1 |
| 0.10.0 | 1 |
| 0.10.1 | 1 |
| 0.10.2 | 1 |
| 0.11.0 | 1 |
| 1.0 | 1 |
| 1.1 | 1 |
| 2.0 | 1 |
| 2.1 | 1 |
| 2.2 | 1 |
| 2.3 | 1 |
| 2.4 | 1 |
| 2.5 | 1 |
| 2.6 | 1 |
| 2.7 | 1 |
| 2.8 | 1 |
| 3.0 | 1 |
| 3.1 | 1 |
| 3.2 | 1 |
| 3.3 | 1 |
| 3.4 | 1 |
| 3.5 | 1 |
| 3.6 | 1 |
| 3.7 | 1 |
| 3.8 | 1 |
| 3.9 | 1 |
| 4.0 | 2 |
| 4.1 | 2 |
| 4.2 | 2 |
Tuning Recommendation
| Profile | Recommended | Why |
|---|---|---|
| broker / throughput | 4 | Doubles log recovery threads from 2 to 4 per data directory, parallelizing startup recovery and shutdown flushing. With thousands of partitions per data dir, 2 threads can bottleneck broker restart time. |
Related Configs
Manage Kafka configs across all your clusters with Conduktor Console — view, compare, and update configurations in one place.