发现公司好多项目都用到memched。并且都是单点，memched服务器 挂了就会影响业务，于是百度之，发现memched不可以集群，也没有看到有什么高可用方案，但是发现了repcached（memched主从复制），结合LVS的NAT模式不同端口转发实现memched双机HA，本次文章记录本人的部署过程，从属实战，没有文件性的说明，不过大牛们一看就懂了。
二、环境：
1、系统环境：CentOS release 6.4 (Final)
2、网络环境
调度机（master）：
vip：172.28.26.100
vip1:172.28.16.100（lvs转发网关 ）
eth1:172.28.26.101 （内网）
eth2:172.28.16.101（lvs转发网段）
调度机（backup）：
eth1:172.28.26.99 （内网）
eth2:172.28.16.99（lvs转发网段）
memched备节点：
eth1:172.28.26.102 （内网）
eth2:172.28.16.102（lvs转发网段）
memched主节点：
eth1:172.28.26.103 （内网）
eth2:172.28.16.103（lvs转发网段）
3、路由策略
调度机（master）：
echo '201 eth1' >> /etc/iproute2/rt_tables
echo 'default table eth1 via 172.28.26.1 dev eth1' > /etc/sysconfig/network-scripts/route-eth1
echo 'from 172.28.26.101/255.255.255.255 table eth1' > /etc/sysconfig/network-scripts/rule-eth1
echo 'from 172.28.26.100/255.255.255.255 table eth1' >> /etc/sysconfig/network-scripts/rule-eth1
echo 'from 172.28.16.101/32 table ZW_LVS_LAN' > /etc/sysconfig/network-scripts/rule-eth2
memched节点1：
echo 'default table ZW_LVS_LAN via 172.28.16.100' > /etc/sysconfig/network-scripts/route-eth2
echo 'from 172.28.16.0/24 table ZW_LVS_LAN' > /etc/sysconfig/network-scripts/rule-eth2
echo '202 ZW_LVS_LAN' >> /etc/iproute2/rt_tables
memched节点2：
echo 'default table ZW_LVS_LAN via 172.28.16.100' > /etc/sysconfig/network-scripts/route-eth2
echo 'from 172.28.16.0/24 table ZW_LVS_LAN' > /etc/sysconfig/network-scripts/rule-eth2
echo '202 ZW_LVS_LAN' >> /etc/iproute2/rt_tables
4、内核参数
fs.file-max = 1000000
kernel.core_uses_pid = 1
kernel.msgmax = 1048560
kernel.msgmnb = 1073741824
kernel.shmall = 4294967296
kernel.shmmax = 68719476736
kernel.sysrq = 0
net.core.netdev_max_backlog = 1048576
net.core.rmem_default = 2097152
net.core.rmem_max = 16777216
net.core.somaxconn = 1048576
net.core.wmem_default = 2097152
net.core.wmem_max = 16777216
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.ip_forward = 1
net.ipv4.ip_local_port_range = 1024 65000
net.ipv4.neigh.default.gc_thresh1 = 10240
net.ipv4.neigh.default.gc_thresh2 = 40960
net.ipv4.neigh.default.gc_thresh3 = 81920
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_intvl = 15
net.ipv4.tcp_keepalive_probes = 5
net.ipv4.tcp_keepalive_time = 30
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 1048576
net.ipv4.tcp_max_tw_buckets = 50000
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_orphan_retries = 3
net.ipv4.tcp_reordering = 5
net.ipv4.tcp_retrans_collapse = 0
net.ipv4.tcp_retries2 = 5
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_sack = 1
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syncookies = 0
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_wmem = 4096 16384 4194304
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv4.conf.eth0.rp_filter = 1 #memched节点不需要
net.ipv4.conf.eth1.rp_filter = 1 #memched节点不需要
net.ipv4.conf.eth2.rp_filter = 1 #memched节点不需要
net.ipv4.conf.all.rp_filter = 0 #memched节点不需要