Common parameters modification of Linux Server

Document descriptor (file descriptors)

/etc/security/limits.conf
Here is the file descriptor limit that the current user allows to open, which can be ulimit -n viewed.
Modify the configuration as follows:

1. * hard nofile 65536
2. root hard nofile 65536
3. * soft nofile 65536
4. root soft nofile 65536

Note: Root and * must be written, this * represents a different account than root (the pit is correct)
Log off and re-login in effect.

Maximum number of connections (max connections)

/etc/sysctl.conf
Here you can set the system's total file descriptor limit (all users), as well as other TCP-related settings.
The maximum number of connections is net.core.somaxconn that this parameter is inconsistent in different Linux cores, so you can set it two times and use a different upper limit.

2. fs.file-max=102400
4. net.ipv4.tcp_slow_start_after_idle = 0
6. net.core.somaxconn = 65535
8. net.ipv4.tcp_keepalive_time=300
10. net.ipv4.tcp_tw_reuse=1
12. net.ipv4.tcp_tw_recycle=1
14. net.ipv4.tcp_no_metrics_save=1
16. net.core.somaxconn=262144
18. net.ipv4.tcp_max_orphans=262144
20. net.ipv4.tcp_synack_retries=2
22. net.ipv4.tcp_syn_retries=2
24. net.ipv4.tcp_syncookies=0
26. net.ipv4.tcp_max_syn_backlog=262144
28. net.core.wmem_max=16777216
30. net.core.rmem_max=16777216
32. net.ipv4.tcp_wmem=4096 4096 16777216
34. net.ipv4.tcp_mem = 786432 2097152 3145728
36. net.ipv4.tcp_rmem=4096 4096 16777216
38. net.core.netdev_max_backlog=30000
40. net.ipv4.ip_local_port_range=5000 65535
42. net.ipv4.tcp_fin_timeout=30
44. net.core.rmem_default = 262144
46. net.core.wmem_default = 262144
48. net.core.netdev_max_backlog=16384
50. net.core.rmem_max=16777216
52. net.core.wmem_max=16777216
54. net.ipv4.tcp_syncookies=1

After modification, the use sysctl -p takes effect.

Note that after the above modifications are complete, many services must be restarted to take effect.

Common parameters modification of Linux Server