lvs 超时问题

客户端 http fsopen 调用偶发遭遇timed out，dmesg 看到入口一台机器报：

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

nf_conntrack: table full, dropping packet.

由于 lvs 架构原因，有做 iptable 策略，增大max 的值，减少timeout 的时间：

net.nf_conntrack_max = 655360

net.netfilter.nf_conntrack_tcp_timeout_established = 1200

其它版本有可能：

net.ipv4.netfilter.ip_conntrack_max = 655350

net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 1200