我每天运行一个网站，访问量约为10万次，最近的平均负载量达到250+。 他们通常是大约0.5-1.5，所以我假设了（D）DOS攻击。 Apache进程的数量可达1000。 但是，到服务器的连接数不会改变（大约600），客户端的最大连接数是20。 它只偶尔发生，当我重新启动apache时，它将自我sorting。 为什么apache决定产生大量的线程，并将我的负载平均值发送到250？
这是顶部的结果：
Normal top: top - 15:07:16 up 1 day, 1:28, 3 users, load average: 1.44, 2.55, 21.83 Tasks: 307 total, 3 running, 304 sleeping, 0 stopped, 0 zombie Cpu(s): 30.2%us, 3.2%sy, 0.0%ni, 64.9%id, 1.5%wa, 0.0%hi, 0.1%si, 0.0%st Mem: 2074128k total, 1836852k used, 237276k free, 21732k buffers Swap: 2096472k total, 56440k used, 2040032k free, 278048k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 16776 apache 16 0 38752 23m 3124 S 20.4 1.2 0:01.32 httpd 16252 apache 15 0 37760 20m 3240 S 5.6 1.0 0:00.46 httpd 16333 apache 15 0 36152 21m 3136 S 5.0 1.1 0:01.16 httpd 17426 apache 15 0 35732 20m 3056 S 3.2 1.0 0:00.16 httpd 17418 apache 16 0 38536 22m 3020 S 2.8 1.1 0:00.14 httpd 16161 apache 16 0 36800 21m 3148 S 2.0 1.1 0:00.63 httpd 15988 apache 15 0 29284 12m 3112 S 1.8 0.6 0:00.20 httpd 17441 mysql 16 0 66656 19m 1988 R 1.4 1.0 0:00.07 mysqld 17442 mysql 16 0 66656 19m 1988 R 1.2 1.0 0:00.06 mysqld 12265 apache 15 0 35916 21m 3148 S 0.8 1.0 0:01.49 httpd 15987 apache 15 0 37616 20m 3224 S 0.6 1.0 0:00.46 httpd 13564 root 15 0 2552 1196 804 R 0.4 0.1 0:00.83 top 17011 apache 15 0 26668 11m 3016 S 0.4 0.6 0:00.05 httpd 409 root 10 -5 0 0 0 S 0.2 0.0 0:21.83 scsi_eh_0 3920 mysql 15 0 66656 19m 1988 S 0.2 1.0 0:26.90 mysqld 9357 apache 18 0 40896 23m 3228 S 0.2 1.2 0:03.36 httpd 11971 apache 18 0 39888 23m 3868 S 0.2 1.1 0:01.55 httpd Abnormal top: top - 09:12:12 up 3 days, 19:33, 1 user, load average: 58.75, 69.17, 58.05 Tasks: 568 total, 2 running, 563 sleeping, 0 stopped, 3 zombie Cpu(s): 5.6%us, 2.3%sy, 0.0%ni, 11.7%id, 79.9%wa, 0.1%hi, 0.4%si, 0.0%st Mem: 2074128k total, 2004008k used, 70120k free, 9008k buffers Swap: 2096472k total, 1009264k used, 1087208k free, 128268k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 14534 mysql 16 0 79764 24m 1824 R 6.0 1.2 0:00.20 mysqld 13903 mysql 16 0 79764 24m 1824 S 2.4 1.2 0:00.13 mysqld 13906 mysql 16 0 79764 24m 1824 S 2.4 1.2 0:00.08 mysqld 14068 mysql 16 0 79764 24m 1824 S 1.8 1.2 0:00.10 mysqld 13862 apache 15 0 35532 15m 1892 D 0.9 0.8 0:00.44 httpd 14316 apache 16 0 26012 6672 1852 S 0.9 0.3 0:00.14 httpd 14787 apache 16 0 27992 8332 1820 D 0.9 0.4 0:00.06 httpd 10588 apache 18 0 39480 13m 1912 D 0.6 0.7 0:01.42 httpd 12457 apache 16 0 39332 12m 2328 D 0.6 0.6 0:00.42 httpd 13564 root 16 0 2684 1180 648 S 0.6 0.1 5:18.00 top 13819 apache 15 0 26688 7352 2276 S 0.6 0.4 0:00.56 httpd 13853 mysql 16 0 79764 24m 1824 S 0.6 1.2 0:00.09 mysqld 14335 apache 16 0 28544 8964 1872 S 0.6 0.4 0:00.30 httpd 442 root 10 -5 0 0 0 D 0.3 0.0 0:53.61 kjournald 6337 apache 15 0 39420 17m 2648 S 0.3 0.9 0:03.46 httpd 9976 apache 18 0 38924 7708 2316 S 0.3 0.4 0:01.44 httpd 9990 apache 15 0 36432 16m 2556 S 0.3 0.8 0:02.23 httpd 这是你的ServerLimit设置和httpd.conf中的其他值的值：
StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 256 MaxClients 256 MaxRequestsPerChild 4000
调低你的ServerLimit到100左右，并减lessMaxRequestPerChild大约1000，所以孩子收获更快。