socket.send.buffer.bytes — Kafka Broker Configuration
The SO_SNDBUF buffer of the socket server sockets. If the value is -1, the OS default will be used.
Description
The SO_SNDBUF buffer of the socket server sockets. If the value is -1, the OS default will be used.
Default Values by Kafka Version
| Kafka Version | Default Value |
|---|---|
| 0.8.0 | 100 * 1024 |
| 0.8.1 | 100 * 1024 |
| 0.8.2 | 100 * 1024 |
| 0.9.0 | 102400 |
| 0.10.0 | 102400 |
| 0.10.1 | 102400 |
| 0.10.2 | 102400 |
| 0.11.0 | 102400 |
| 1.0 | 102400 |
| 1.1 | 102400 |
| 2.0 | 102400 |
| 2.1 | 102400 |
| 2.2 | 102400 |
| 2.3 | 102400 |
| 2.4 | 102400 |
| 2.5 | 102400 |
| 2.6 | 102400 (100 kibibytes) |
| 2.7 | 102400 (100 kibibytes) |
| 2.8 | 102400 (100 kibibytes) |
| 3.0 | 102400 (100 kibibytes) |
| 3.1 | 102400 (100 kibibytes) |
| 3.2 | 102400 (100 kibibytes) |
| 3.3 | 102400 (100 kibibytes) |
| 3.4 | 102400 (100 kibibytes) |
| 3.5 | 102400 (100 kibibytes) |
| 3.6 | 102400 (100 kibibytes) |
| 3.7 | 102400 (100 kibibytes) |
| 3.8 | 102400 (100 kibibytes) |
| 3.9 | 102400 (100 kibibytes) |
| 4.0 | 102400 (100 kibibytes) |
| 4.1 | 102400 (100 kibibytes) |
| 4.2 | 102400 (100 kibibytes) |
Tuning Recommendation
| Profile | Recommended | Why |
|---|---|---|
| broker / throughput | 1048576 | Increasing the OS TCP send buffer to 1MB allows the kernel to buffer more outgoing fetch-response bytes, critical on high-latency links or when consumers are remote. The bandwidth-delay product on a 1Gbps link at 1ms RTT is already 125KB — larger buffers avoid TCP stalls. |
| broker / latency | 65536 | Smaller send buffer reduces buffering delay for small responses. The default 100KB buffer may delay small fetch responses while waiting to fill. |
Related Configs
socket.receive.buffer.bytes · socket.request.max.bytes · replica.socket.receive.buffer.bytes
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