测试调优

EMQ 消息服务器1.x版本MQTT连接压力测试到130万,在一台8核心、32G内存的CentOS服务器上。

100万连接测试所需的Linux内核参数,网络协议栈参数,Erlang虚拟机参数,emqttd消息服务器参数设置如下:

Linux操作系统参数

系统全局允许分配的最大文件句柄数:

# 2 millions system-wide
sysctl -w fs.file-max=2097152
sysctl -w fs.nr_open=2097152
echo 2097152 > /proc/sys/fs/nr_open

允许当前会话/进程打开文件句柄数:

ulimit -n 1048576

/etc/sysctl.conf

持久化’fs.file-max’设置到/etc/sysctl.conf文件:

fs.file-max = 1048576

/etc/systemd/system.conf设置服务最大文件句柄数:

DefaultLimitNOFILE=1048576

/etc/security/limits.conf

/etc/security/limits.conf持久化设置允许用户/进程打开文件句柄数:

*      soft   nofile      1048576
*      hard   nofile      1048576

TCP协议栈网络参数

并发连接backlog设置:

sysctl -w net.core.somaxconn=32768
sysctl -w net.ipv4.tcp_max_syn_backlog=16384
sysctl -w net.core.netdev_max_backlog=16384

可用知名端口范围:

sysctl -w net.ipv4.ip_local_port_range='1000 65535'

TCP Socket读写Buffer设置:

sysctl -w net.core.rmem_default=262144
sysctl -w net.core.wmem_default=262144
sysctl -w net.core.rmem_max=16777216
sysctl -w net.core.wmem_max=16777216
sysctl -w net.core.optmem_max=16777216

#sysctl -w net.ipv4.tcp_mem='16777216 16777216 16777216'
sysctl -w net.ipv4.tcp_rmem='1024 4096 16777216'
sysctl -w net.ipv4.tcp_wmem='1024 4096 16777216'

TCP连接追踪设置:

sysctl -w net.nf_conntrack_max=1000000
sysctl -w net.netfilter.nf_conntrack_max=1000000
sysctl -w net.netfilter.nf_conntrack_tcp_timeout_time_wait=30

TIME-WAIT Socket最大数量、回收与重用设置:

net.ipv4.tcp_max_tw_buckets=1048576

# 注意: 不建议开启該设置,NAT模式下可能引起连接RST
# net.ipv4.tcp_tw_recycle = 1
# net.ipv4.tcp_tw_reuse = 1

FIN-WAIT-2 Socket超时设置:

net.ipv4.tcp_fin_timeout = 15

Erlang虚拟机参数

优化设置Erlang虚拟机启动参数,配置文件emqttd/etc/emq.conf:

## Erlang Process Limit
node.process_limit = 2097152

## Sets the maximum number of simultaneously existing ports for this system
node.max_ports = 1048576

EMQ消息服务器参数

设置TCP监听器的Acceptor池大小,最大允许连接数。配置文件emqttd/etc/emq.conf:

## TCP Listener
listener.tcp.external = 0.0.0.0:1883
listener.tcp.external.acceptors = 64
listener.tcp.external.max_clients = 1000000

测试客户端设置

测试客户端服务器在一个接口上,最多只能创建65000连接:

sysctl -w net.ipv4.ip_local_port_range="500 65535"
echo 1000000 > /proc/sys/fs/nr_open
ulimit -n 100000

emqtt_benchmark

并发连接测试工具: http://github.com/emqtt/emqtt_benchmark