High-concurrency Linux kernel Network Parameter Tuning

Adjust Linux (ubuntu8.0.4) kernel parameters to meet high-concurrency access and solve a large number of time_wait and SYN Attacks:
1 sudo VI/etc/sysctl. conf
Edit and add at the bottom:
Net. ipv4.tcp _ fin_timeout = 30
Net. ipv4.tcp _ keepalive_time = 1200
Net. Route 4.route. gc_timeout = 100
Net. ipv4.ip _ local_port_range = 1024 65000
Net. ipv4.tcp _ tw_reuse = 1
Net. ipv4.tcp _ tw_recycle = 1
Net. ipv4.tcp _ syn_retries = 1
Net. ipv4.tcp _ synack_retries = 1
Net. ipv4.tcp _ max_syn_backlog = 262144
Net. Core. netdev_max_backlog = 262144
Net. Core. somaxconn = 262144
Net. ipv4.tcp _ mem = 94500000 915000000 927000000
Save and exit
2 sudo/sbin/sysctl-P
Take effect immediately (in practice, if it cannot take effect immediately, restart the host to take effect)

Use the following command to monitor connections in different States:
1 netstat-N | awk '/^ TCP/{++ s [$ NF]} end {for (a in S) print a, s [a]}' 
2 CAT/proc/NET/sockstat 
3. check whether any exception log exists: dmesg 
4. view the number of current IP addresses and the number of connections per IP Address: 
Netstat-an | grep 80 | awk '{print $5}' | awk 'begin {FS = ": "} NF = 2 {print $1} NF = 5 {print $4} '| sort | uniq-c | sort-n

Default Value Recovery:
Net. ipv4.tcp _ fin_timeout = 60
Net. ipv4.tcp _ keepalive_time = 7200
Net. Route 4.route. gc_timeout = 300
Net. ipv4.ip _ local_port_range = 32768 61000
Net. ipv4.tcp _ tw_reuse = 0
Net. ipv4.tcp _ tw_recycle = 0
Net. ipv4.tcp _ syn_retries = 5
Net. ipv4.tcp _ synack_retries = 5
Net. ipv4.tcp _ max_syn_backlog = 1024
Net. Core. netdev_max_backlog = 1000
Net. Core. somaxconn = 128
Net. ipv4.tcp _ mem = 853440 1137920 1706880

In the actual production environment, if the number of connections for a single machine reaches, nginx works normally.

Server optimization recommendationsArticle: Http://blog.sina.com.cn/s/blog_466c66400100bi2n.html ~ Type = v5_one & label = rela_prevarticle