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<推荐> 本文的完美排版/最后更新修正版本：http://www.noobu.com/0510_apache_mysql_sysctl_tweak.html <推荐> O #5`mo  
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人们常说，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。这个是对的，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。 8qwPk4  
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配置Sysctl zKFiCP K  
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编辑此文件： em
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nano -w /etc/sysctl.conf RY
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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： CJt(c,!z  
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# Controls source route verification gP?.io9Oi  
# Default should work for all interfaces v d
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net.ipv4.conf.default.rp_filter = 1 O7yIFqI=/  
# net.ipv4.conf.all.rp_filter = 1 _@O.EksY3r  
# net.ipv4.conf.lo.rp_filter = 1 oA4<AJ2  
# net.ipv4.conf.eth0.rp_filter = 1 JxQGL{) >  
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# Disables IP source routing <,Fj}T-  
# Default should work for all interfaces +[Q`I*C  
net.ipv4.conf.default.accept_source_route = 0 4GexYDk'#  
# net.ipv4.conf.all.accept_source_route = 0 Im@Yx^gc  
# net.ipv4.conf.lo.accept_source_route = 0 hv)d  
# net.ipv4.conf.eth0.accept_source_route = 0 qK
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# Controls the System Request debugging functionality of the kernel p&ZLd
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kernel.sysrq = 0 VX e7b  
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# Controls whether core dumps will append the PID to the core filename. bP{uZnOM2P  
# Useful for debugging multi-threaded applications. IvM>z03  
kernel.core_uses_pid = 1 P;ovPyoO  
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# Increase maximum amount of memory allocated to shm t#=FFQOt  
# Only uncomment if needed! %SwhNn  
# kernel.shmmax = 67108864 n4/Jx*  
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# Disable ICMP Redirect Acceptance u-HBmL  
# Default should work for all interfaces m]'P3^<{P  
net.ipv4.conf.default.accept_redirects = 0 qp2&Z8S\D  
# net.ipv4.conf.all.accept_redirects = 0 q 1+{MPJ  
# net.ipv4.conf.lo.accept_redirects = 0 `_>44!M  
# net.ipv4.conf.eth0.accept_redirects = 0 48n7<M;I  
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# Enable Log Spoofed Packets, Source Routed Packets, Redirect Packets d` 4F  
# Default should work for all interfaces hbE~.[Y2r  
net.ipv4.conf.default.log_martians = 1 |&U{ z?  
# net.ipv4.conf.all.log_martians = 1 p((a(Q/
  
# net.ipv4.conf.lo.log_martians = 1 +F+M[ef<ws  
# net.ipv4.conf.eth0.log_martians = 1 (!%9#  
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# Decrease the time default value for tcp_fin_timeout connection (nAL;:$x2  
net.ipv4.tcp_fin_timeout = 25 u(i=-PN_<  
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# Decrease the time default value for tcp_keepalive_time connection @MO/LvD  
net.ipv4.tcp_keepalive_time = 1200 )3k?{1:  
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# Turn on the tcp_window_scaling LVT:oIQ  
net.ipv4.tcp_window_scaling = 1 aK/fZ$Qc  
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# Turn on the tcp_sack U7Oa 13Qz  
net.ipv4.tcp_sack = 1 G.`
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# tcp_fack should be on because of sack `]^W#6l
 
net.ipv4.tcp_fack = 1 \*[DR R0  
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# Turn on the tcp_timestamps *V4%&&{  
net.ipv4.tcp_timestamps = 1 wl&T9
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# Enable TCP SYN Cookie Protection e^oGiL~  
net.ipv4.tcp_syncookies = 1 un4fnoc  
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# Enable ignoring broadcasts request g?Tev^D  
net.ipv4.icmp_echo_ignore_broadcasts = 1 /Ry%K4$  
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# Enable bad error message Protection /# ]eVD  
net.ipv4.icmp_ignore_bogus_error_responses = 1 tjt^R$[@  
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# Make more local ports available vi *A5  
# net.ipv4.ip_local_port_range = 1024 65000 l)*(UZ"  

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# Set TCP Re-Ordering value in kernel to ‘5′ `YC7+`q  
net.ipv4.tcp_reordering = 5 8-NycG&)  
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# Lower syn retry rates tiE|%jOzt  
net.ipv4.tcp_synack_retries = 2 P O 5Wi  
net.ipv4.tcp_syn_retries = 3 V~[b`&F  
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# Set Max SYN Backlog to ‘2048′ 8 E\zjT!#\  
net.ipv4.tcp_max_syn_backlog = 2048 myR{}G  
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# Various Settings mdEJ'];AH  
net.core.netdev_max_backlog = 1024 fV|uKs(W  
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# Increase the maximum number of skb-heads to be cached __'4Qt  
net.core.hot_list_length = 256 aE5-b ub c  
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# Increase the tcp-time-wait buckets pool size o'$"MC+  
net.ipv4.tcp_max_tw_buckets = 360000 49Jnp>h  
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# This will increase the amount of memory available for socket input/output queues 9Vm1q!lE  
net.core.rmem_default = 65535 ZX:rqc  
net.core.rmem_max = 8388608 adP :{j  
net.ipv4.tcp_rmem = 4096 87380 8388608 -{cmi ,oy  
net.core.wmem_default = 65535 N x&/p$d  
net.core.wmem_max = 8388608 m>vwpRBOA  
net.ipv4.tcp_wmem = 4096 65535 8388608 k)n b<JW|r  
net.ipv4.tcp_mem = 8388608 8388608 8388608 2xLtJR4L  
net.core.optmem_max = 40960 ki'$P.v{$w  
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如果希望屏蔽别人 ping 你的主机，则加入以下代码： T/'z,,Y  
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# Disable ping requests s-"KABE
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net.ipv4.icmp_echo_ignore_all = 1 uB I/3aQ  
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编辑完成后，请执行以下命令使变动立即生效： "] V\Y!  
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/sbin/sysctl -p be8T<F  
/sbin/sysctl -w net.ipv4.route.flush=1 sGu.G  
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MySQL优化 n&:ohOH%  
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编辑MySQL的配置文件： PB@IPnB-  
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nano /etc/my.cnf E]mm^i`|  
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输入以下内容： BY~Tc5  
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connect_timeout=15 -P}A26qB  
interactive_timeout=100 6k t,q0  
join_buffer_size=1M xxur4@p!  
key_buffer=128M G[>
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max_allowed_packet=16M S"&Gutu3o  
max_connections=500 gF,=rT1:>r  
max_connect_errors=10 V[(fE=cIN~  
myisam_sort_buffer_size=64M NF
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read_buffer_size=1M v*!N}1+J  
read_rnd_buffer_size=768K W_}j~[&  
sort_buffer_size=1M ],weqs  
table_cache=1024 or*{P=m+R  
thread_cache_size=100 f- XUto  
thread_concurrency=4 /Z6lnm7wJ  
wait_timeout=300 84WDR?  
query_cache_size=32M -W9DH^EL<  
query_cache_limit=1M Q/SO%E`E  
query_cache_type=1 ;d}>8w&tfy  
skip-innodb Z;G*wM"  
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请注意，以上配置适用于512M~1024M内存，如内存更大的话请自行做调整。给项目增加内存会加快速度，但是使用过多的内存而导致启用swap的话，会极大的导致系统效率下降。其中 thread_concurrency 这项配置，单CPU的话请设置为2，双CPU的话请设置为4。 h,$CJdDY]  
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Apache优化 Ga5s9wC  
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以下优化适用于 Apache 1.3 系列，如果你用的是 2.0 系列的话，请自行做调整和判断。 RyK~"CWT  
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确认 Apache 的配置文件位置并开始编辑： QwX81*nx  
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locate httpd.conf Kn->R9Tl  
nano -w /path/to/httpd.conf )'m;a_r`  
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httpd.conf的文件有许多内容，笔者就拿出需要做优化的： h)Fc<,vwBE  
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KeepAlive On kFE9}0-  
MaxKeepAliveRequests 1000 {{G3^ysa  
KeepAliveTimeout 3 0JtM|Mg  
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MinSpareServers 8 ZY8.p  
MaxSpareServers 13 HsTY*^V  
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MaxRequestsPerChild 50 '1DY5`i{  
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将 KeepAliveTimeout 设定到较小的数字将有助于减少服务器上的无用等待链接，一定程度上能增加服务器负载。 K3\a~_0
 
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另外，下面这条不算优化，但是是Apache安全相关： +pgHCzwJE  
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ServerSignature Off (hOD  
ServerTokens ProductOnly w tGS"L  
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将 ServerSignature 关闭，并增加 ServerTokens ProductOnly 可以使常人无法检测到Apache的实际版本号，有助于Apache的安全。 R\ 8[6H  

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以上所做的这些优化在某种程度上会增强服务器的负载性能。但请注意，最佳的配置是实践出来的。