服务器优化——Sysctl、Apache、MySQL

服务器的负载能力，很大程度上取决于系统管理员的配置和优化能力。相同的硬件、不同的软件配置，会造成截然不同的效果。下面我将给大家介绍一下如何优化 sysctrl, Apache 以及 MySQL 。请注意，所有配置均为取决于个人，请根据自己的实际情况做调整。
　　
　　配置Sysctl
　　
　　编辑此文件：
　　
　　nano -w /etc/sysctl.conf
　　
　　如果该文件为空，则输入以下内容，否则请根据情况自己做调整：
　　
　　# Controls source route verification
　　# Default should work for all interfaces
　　net.ipv4.conf.default.rp_filter = 1
　　# net.ipv4.conf.all.rp_filter = 1
　　# net.ipv4.conf.lo.rp_filter = 1
　　# net.ipv4.conf.eth0.rp_filter = 1
　　
　　# Disables IP source routing
　　# Default should work for all interfaces
　　net.ipv4.conf.default.accept_source_route = 0
　　# net.ipv4.conf.all.accept_source_route = 0
　　# net.ipv4.conf.lo.accept_source_route = 0
　　# net.ipv4.conf.eth0.accept_source_route = 0
　　
　　# Controls the System Request debugging functionality of the kernel
　　kernel.sysrq = 0
　　
　　# Controls whether core dumps will append the PID to the core filename.
　　# Useful for debugging multi-threaded applications.
　　kernel.core_uses_pid = 1
　　
　　# Increase maximum amount of memory allocated to shm
　　# Only uncomment if needed!
　　# kernel.shmmax = 67108864
　　
　　# Disable ICMP Redirect Acceptance
　　# Default should work for all interfaces
　　net.ipv4.conf.default.accept_redirects = 0
　　# net.ipv4.conf.all.accept_redirects = 0
　　# net.ipv4.conf.lo.accept_redirects = 0
　　# net.ipv4.conf.eth0.accept_redirects = 0
　　
　　# Enable Log Spoofed Packets, Source Routed Packets, Redirect Packets
　　# Default should work for all interfaces
　　net.ipv4.conf.default.log_martians = 1
　　# net.ipv4.conf.all.log_martians = 1
　　# net.ipv4.conf.lo.log_martians = 1
　　# net.ipv4.conf.eth0.log_martians = 1
　　
　　# Decrease the time default value for tcp_fin_timeout connection
　　net.ipv4.tcp_fin_timeout = 25
　　
　　# Decrease the time default value for tcp_keepalive_time connection
　　net.ipv4.tcp_keepalive_time = 1200
　　
　　# Turn on the tcp_window_scaling
　　net.ipv4.tcp_window_scaling = 1
　　
　　# Turn on the tcp_sack
　　net.ipv4.tcp_sack = 1
　　
　　# tcp_fack should be on because of sack
　　net.ipv4.tcp_fack = 1
　　
　　# Turn on the tcp_timestamps
　　net.ipv4.tcp_timestamps = 1
　　
　　# Enable TCP SYN Cookie Protection
　　net.ipv4.tcp_syncookies = 1
　　
　　# Enable ignoring broadcasts request
　　net.ipv4.icmp_echo_ignore_broadcasts = 1
　　
　　# Enable bad error message Protection
　　net.ipv4.icmp_ignore_bogus_error_responses = 1
　　
　　# Make more local ports available
　　# net.ipv4.ip_local_port_range = 1024 65000
　　
　　# Set TCP Re-Ordering value in kernel to ‘5′
　　net.ipv4.tcp_reordering = 5
　　
　　# Lower syn retry rates
　　net.ipv4.tcp_synack_retries = 2
　　net.ipv4.tcp_syn_retries = 3
　　
　　# Set Max SYN Backlog to ‘2048′
　　net.ipv4.tcp_max_syn_backlog = 2048
　　
　　# Various Settings
　　net.core.netdev_max_backlog = 1024
　　
　　# Increase the maximum number of skb-heads to be cached
　　net.core.hot_list_length = 256
　　
　　# Increase the tcp-time-wait buckets pool size
　　net.ipv4.tcp_max_tw_buckets = 360000
　　
　　# This will increase the amount of memory available for socket input/output queues
　　net.core.rmem_default = 65535
　　net.core.rmem_max = 8388608
　　net.ipv4.tcp_rmem = 4096 87380 8388608
　　net.core.wmem_default = 65535
　　net.core.wmem_max = 8388608
　　net.ipv4.tcp_wmem = 4096 65535 8388608
　　net.ipv4.tcp_mem = 8388608 8388608 8388608
　　net.core.optmem_max = 40960