Linux系统优化部分内核参数调优中文注释

Linux系统优化部分内核参数调优中文注释

应用服务器sysctl.conf部分参数

## network configurations

net.ipv4.ip_forward = 0 # IP packet forwarding

net.ipv4.tcp_tw_reuse=1

net.ipv4.tcp_tw_recycle=1

net.ipv4.tcp_fin_timeout=30 #60,每条至多占 1.5K 的内存

net.ipv4.tcp_keepalive_time=1800 #7200

net.core.netdev_max_backlog=3000 #1000每个网络接口接收数据包的速率比内核处理这些包的速率快时，允许送到队列的数据包的最大数目

net.ipv4.tcp_max_syn_backlog=4096 #1024 增加TCP SYN队列长度，使系统可以处理更多的并发连接

net.core.wmem_default = 2097152 #108544,系统套接字缓冲区

net.core.rmem_default = 2097152 #108544,系统套接字缓冲区

net.core.rmem_max=16777216 #131071,系统套接字缓冲区

net.core.wmem_max=16777216 #131071,系统套接字缓冲区

net.ipv4.tcp_rmem=4096 87380 16777216 #4096 87380 174760, TCP接收缓冲区

net.ipv4.tcp_wmem=4096 65536 16777216 #4096 16384 131072, TCP发送缓冲区

net.ipv4.tcp_mem = 786432 1048576 1572864 # Out of socket memory

net.ipv4.tcp_syncookies=1 #0,防SyncFlood攻击

net.ipv4.ip_local_port_range = 32768 61000 #用于向外连接的端口范围,这是默认值

net.ipv4.tcp_max_tw_buckets = 5000 #180000,同时保持TIME_WAIT套接字的最大数量

#以下可能需要加载ip_conntrack模块 modprobe ip_conntrack

# net.ipv4.ip_conntrack_max=6553600

# net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 1800

# net.ipv4.netfilter.ip_conntrack_max=6553600

# net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait=120

# net.ipv4.netfilter.ip_conntrack_tcp_timeout_close_wait=60

# net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait=120

# net.ipv4.icmp_echo_ignore_all = 1 #0, Disable ping requests

# net.ipv4.icmp_echo_ignore_broadcasts = 1 #1, Enable ignoring broadcasts request

net.ipv4.neigh.default.gc_thresh3 = 40960 #1024

net.ipv4.neigh.default.gc_thresh2 = 20480 #512

net.ipv4.neigh.default.gc_thresh1 = 10240 #128

##以上三条语句可以解决内核中出现的如下两行错误

#Linux kernel: printk: xxxxx messages suppressed.

#Linux kernel: Neighbour table overflow.

## system configurations

fs.file-max = 372901 #23712, 整个系统所有可打开文件总数的限制, 可按256/4M内存计算值。

# ulimit -n 10000 #某一程序可打开文件 总数的限制

# kernel.ctrl-alt-del = 1 #0,Disable CTR+ALT+DEL Restart Keys

附:sysctl.conf

fs.file-max = 372901

net.ipv4.tcp_tw_reuse=1

net.ipv4.tcp_tw_recycle=1

net.ipv4.tcp_fin_timeout=30

net.ipv4.tcp_keepalive_time=1800

net.core.netdev_max_backlog=3000

net.ipv4.tcp_max_syn_backlog=4096

net.core.wmem_default = 2097152

net.core.rmem_default = 2097152

net.ipv4.tcp_rmem=4096 87380 16777216

net.core.rmem_max=33554432

net.ipv4.tcp_wmem=4096 65536 16777216

net.core.wmem_max=33554432

net.ipv4.tcp_mem = 786432 1048576 1572864

net.ipv4.tcp_syncookies=1

net.ipv4.tcp_max_tw_buckets = 180000

net.ipv4.ip_conntrack_max=6553600

net.ipv4.netfilter.ip_conntrack_max=6553600

net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait=60

net.ipv4.netfilter.ip_conntrack_tcp_timeout_close_wait=30

net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait=60

net.ipv4.ip_local_port_range = 32768 61000