79 lines
2.5 KiB
Markdown
79 lines
2.5 KiB
Markdown
[English](bbr.md) | [中文](bbr-zh.md)
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# Advanced usage: Deploy Google BBR congestion control algorithm
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Google BBR is a congestion control algorithm that could significantly increase server throughput and reduce latency.
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Google BBR has been built into Linux kernel 4.9 and higher, but needs to be manually turned on.
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To learn more about the Google BBR algorithm, see this [official blog](https://cloud.google.com/blog/products/networking/tcp-bbr-congestion-control-comes-to-gcp-your-internet-just-got-faster) or this [official repository](https://github.com/google/bbr).
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## Prepare
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You can check the current Linux kernel version with the command `uname -r`. When the version is greater than or equal to 4.9, you can deploy BBR directly by referring to the [instructions below](#deploy-google-bbr).
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Generally speaking, the kernel versions of Ubuntu 18.04+, Debian 10+, CentOS 8+ and RHEL 8+ are greater than 4.9. But for Amazon Linux 2, you need to update the kernel in the following ways before deploying Google BBR.
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### Amazon Linux 2
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Amazon Linux 2 provides newer versions of the verified Linux kernel, which can be installed from the Extras repository.
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1. Install `kernel-ng` from the Extras repository
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```bash
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sudo amazon-linux-extras install kernel-ng
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```
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2. Update packages
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```bash
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sudo yum update
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```
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3. Restart the system
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```bash
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sudo reboot
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```
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4. Check the Linux kernel version
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```bash
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uname -r
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```
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## Deploy Google BBR
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In this section, we will start Google BBR by modifying the configuration file.
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1. Backup `/etc/sysctl.conf`
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```bash
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sudo cp /etc/sysctl.conf /etc/sysctl.conf.backup
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```
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2. Modify `/etc/sysctl.conf`
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```bash
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sudo vim /etc/sysctl.conf
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```
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Add the following lines to the file
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```
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net.core.default_qdisc = fq
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net.ipv4.tcp_congestion_control = bbr
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```
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3. Enable Google BBR
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First, check your server's kernel version using `uname -r`.
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For kernel versions >= 4.20, apply `sysctl` settings:
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```bash
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sudo sysctl -p
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```
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For kernel versions < 4.20, you must reboot the server:
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```bash
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sudo reboot
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```
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4. Check Google BBR status
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```bash
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sudo sysctl net.ipv4.tcp_available_congestion_control
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# net.ipv4.tcp_available_congestion_control = reno cubic bbr
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sudo sysctl -n net.ipv4.tcp_congestion_control
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# bbr
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lsmod | grep bbr
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# tcp_bbr 16384 0
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```
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## Document author
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Copyright (C) 2022 [Leo Liu](https://github.com/optimusleobear)
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Translated by [Lin Song](https://github.com/hwdsl2)
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