redis属于单进程的服务，它主要受内存、CPU、磁盘IO（主要是做持久化），如果服务器配置比较高，多核CPU、高内存的服务器，可以考虑做redis多实例。做多实例之前，首先要考虑CPU和内存的利用，我在测试的时候发现，redis在QPS为6-8W左右的时候，这个redis所在的逻辑CPU核的负载就在100%左右，所以要优化CPU使用这块，目前一般是是做网卡软中断来实现平衡这种单进程使用CPU过高的情况，不过需要网卡支持网卡软中断，效果不错。

   多实例redis的管理，涉及到监控、服务的管理等，这里只说redis多实例的重启。以下是多实例的重启脚本，仅供交流参考：

#!/usr/bin/env python# -*- coding: utf-8 -*-import redis,threading,sys,socket,time,osfrom multiprocessing import Pooldef port_check(host,port):    POOL = redis.ConnectionPool(host=host, port=port)    my_server = redis.Redis(connection_pool=POOL)    try:        a = my_server.ping()        if a:            return 1        else:            return 0    except Exception,e:        return 0def shutdown_server(host,port):    flag = port_check(host,port)    if flag == 1:        POOL = redis.ConnectionPool(host=host, port=port)        my_server = redis.Redis(connection_pool=POOL)        my_server.shutdown()        while 1:            flag = port_check(host,port)            if flag == 0:                print "%s:%s is Shutdown OK" % (host,port)                break            else:                time.sleep(1)    else:        print "%s:%s is Shutdown alreaday" % (host,port)def start_server(host,port):    flag = port_check(host,port)    if flag == 0:        start_conm = "/usr/local/bin/redis-server /usr/local/redis/etc/redis_%s.conf" % port        os.popen(start_conm)        time.sleep(3)        i = 0        while 1:#每5s检测一次redis ping,持续一分钟，1分钟没有起来认为启动失败            flag = port_check(host,port)            if flag == 1:                print "%s:%s is Start OK" % (host,port)                break            else:                if i > 12:                    print "%s:%s is Start Error" % (host,port)                    break                else:                    time.sleep(5)                    i = i + 1    else:        print "%s:%s is Start alreaday" % (host,port)def restart(host,port):    shutdown_server(host,port)    start_server(host,port)def main():    server_list = ["127.0.0.1:6379","127.0.0.1:16379"]    pool = Pool(processes=3)    for i in server_list:        aa = i.split(':')        host = aa[0]        port = int(aa[1])        results = pool.apply_async(restart, (host,port))    pool.close()    pool.join()    if results.successful():        print 'successful'if __name__=="__main__":    main()