繼 Apache 的 MaxClients 與 MaxRequestsPerChild 之後
MaxClients 大致上是，用
ps -ylC httpd --sort:rss
找出其中一個 apache 程序佔用的 memory 量 (KB)
MaxClients = All memory / one apache memory
再來用系統全部的 memory 除以一個 apache 程序佔用的 memory ，就大約是我可以用多少 MaxClients
不過也不一定要用這算出來的值，自己適情況調大
以下找一些別人寫好的 script 可以參考用
參考 : http://techietent.blogspot.tw/2013/05/script-to-calculate-maxclients-in-apache.html
#!/bin/bash
tome=$(free -m | grep -i mem | awk '{print $2}')
htps=$(ps -aylC httpd |grep "httpd" |awk '{print $8'} |sort -n |tail -n 1)
mysme=$(ps aux | grep 'mysql' | awk '{print $6}' |sort -n |tail -n 1)
rafa=1024
nmysme=$(expr $mysme / $rafa)
nhtps=$(expr $htps / $rafa)
echo -e "\nTotal Memory = $tome"
echo -e "Largest httpd Process = $nhtps"
echo -e "Mysql Memory = $nmysme"
maxc=`expr $tome - $nmysme`
maxcl=`expr $maxc / $nhtps`
echo -e "\nSo, The MaxClients = $maxcl"
echo -e "(we can use nearest round of value from $maxcl)"
輸出結果
Total Memory = 490 Largest httpd Process = 6 Mysql Memory = 43 So, The MaxClients = 74 (we can use nearest round of value from 74)
參考 : http://blog.strictly-software.com/2013/07/apache-performance-tuning-bash-script.html
這一個會停用 apache
#!/bin/bash
echo "Calculate MaxClients by dividing biggest Apache thread by free memory"
if [ -e /etc/debian_version ]; then
APACHE="apache2"
elif [ -e /etc/redhat-release ]; then
APACHE="httpd"
fi
APACHEMEM=$(ps -aylC $APACHE |grep "$APACHE" |awk '{print $8'} |sort -n |tail -n 1)
APACHEMEM=$(expr $APACHEMEM / 1024)
SQLMEM=$(ps -aylC mysqld |grep "mysqld" |awk '{print $8'} |sort -n |tail -n 1)
SQLMEM=$(expr $SQLMEM / 1024)
echo "Stopping $APACHE to calculate the amount of free memory"
/etc/init.d/$APACHE stop &> /dev/null
TOTALFREEMEM=$(free -m |head -n 2 |tail -n 1 |awk '{free=($4); print free}')
TOTALMEM=$(free -m |head -n 2 |tail -n 1 |awk '{total=($2); print total}')
SWAP=$(free -m |head -n 4 |tail -n 1 |awk '{swap=($3); print swap}')
MAXCLIENTS=$(expr $TOTALFREEMEM / $APACHEMEM)
MINSPARESERVERS=$(expr $MAXCLIENTS / 4)
MAXSPARESERVERS=$(expr $MAXCLIENTS / 2)
echo "Starting $APACHE again"
/etc/init.d/$APACHE start &> /dev/null
echo "Total memory $TOTALMEM"
echo "Free memory $TOTALFREEMEM"
echo "Amount of virtual memory being used $SWAP"
echo "Largest Apache Thread size $APACHEMEM"
echo "Amount of memory taking up by MySQL $SQLMEM"
if [[ SWAP > TOTALMEM ]]; then
ERR="Virtual memory is too high"
else
ERR="Virtual memory is ok"
fi
echo "$ERR"
echo "Total Free Memory $TOTALFREEMEM"
echo "MaxClients should be around $MAXCLIENTS"
echo "MinSpareServers should be around $MINSPARESERVERS"
echo "MaxSpareServers should be around $MAXSPARESERVERS"
輸出
Calculate MaxClients by dividing biggest Apache thread by free memory Stopping httpd to calculate the amount of free memory Starting httpd again Total memory 490 Free memory 95 Amount of virtual memory being used 542 Largest Apache Thread size 23 Amount of memory taking up by MySQL 42 Virtual memory is ok Total Free Memory 95 MaxClients should be around 4 MinSpareServers should be around 1 MaxSpareServers should be around 2
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