Memcached 是一個高性能的分布式內存對象緩存系統，用於動態 Web 應用以減輕數據庫負載。

它通過在內存中緩存數據和對象來減少讀取數據庫的次數，從而提高動態、數據庫驅動網站的速度。

Memcached 基於 key/value 的 hashmap。其守護進程 ( daemon ) 是用 C 寫的，但是客戶端可以用任何語言來編寫，並通過 memcached 協議與守護進程通信。

以下介紹 Memcached 安裝方法 :

yum -y install libevent libevent-devel
wget https://memcached.org/latest
mv lastest memcached.tar.gz

./configure --prefix=/opt/memcached
make && make test && make install

touch /etc/init.d/memcached

編輯啟動檔

vim /etc/init.d/memcached

#! /bin/sh
#
# chkconfig: - 55 45
# description:  The memcached daemon is a network memory cache service.
# processname: memcached
# config: /etc/sysconfig/memcached
# pidfile: /var/run/memcached/memcached.pid

# Standard LSB functions
#. /lib/lsb/init-functions

# Source function library.
. /etc/init.d/functions

PORT=11211
USER=nobody
MAXCONN=1024
CACHESIZE=384
OPTIONS=""

if [ -f /etc/sysconfig/memcached ];then
        . /etc/sysconfig/memcached
fi

# Check that networking is up.
. /etc/sysconfig/network

if [ "$NETWORKING" = "no" ]
then
        exit 0
fi

RETVAL=0
prog="memcached"

start () {
        echo -n $"Starting $prog: "
        # insure that /var/run/memcached has proper permissions
    if [ "stat -c %U /var/run/memcached" != "$USER" ]; then
        chown $USER /var/run/memcached
    fi

        daemon --pidfile /var/run/memcached/memcached.pid /opt/memcached/bin/memcached -d -p $PORT -u $USER  -m $CACHESIZE -c $MAXCONN -P /var/run/memcached/memcached.pid $OPTIONS
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && touch /var/lock/subsys/memcached
}
stop () {
        echo -n $"Stopping $prog: "
        killproc -p /var/run/memcached/memcached.pid /opt/memcached/bin/memcached
        RETVAL=$?
        echo
        if [ $RETVAL -eq 0 ] ; then
            rm -f /var/lock/subsys/memcached
            rm -f /var/run/memcached.pid
        fi
}

restart () {
        stop
        start
}

# See how we were called.
case "$1" in
  start)
        start
        ;;
  stop)
        stop
        ;;
  status)
        status memcached
        ;;
  restart|reload|force-reload)
        restart
        ;;
  condrestart)
        [ -f /var/lock/subsys/memcached ] && restart || :
        ;;
  *)
        echo $"Usage: $0 {start|stop|status|restart|reload|force-reload|condrestart}"
        exit 1
esac

exit $?

設定自動啟動服務

chmod 755 /etc/init.d/memcached
chkconfig --add memcached
chkconfig memcached on