分类： LINUX
2009-03-16 18:41:22
用netstat命令发现大量的TIME_WAIT现象：
netstat -ae|grep 1521|grep
root
……
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT
root
TIME_WAIT root
TIME_WAIT root
TIME_WAIT root
检查net.ipv4.tcp_tw当前值，将当前的值更改为1分钟：
[root@aaa1 ~]# sysctl -a|grep
net.ipv4.tcp_tw
net.ipv4.tcp_tw_reuse = 0
net.ipv4.tcp_tw_recycle =
0
[root@aaa1 ~]#
vi /etc/sysctl
增加或修改net.ipv4.tcp_tw值：
net.ipv4.tcp_tw_reuse =
1
net.ipv4.tcp_tw_recycle = 1
使内核参数生效：
[root@aaa1 ~]# sysctl -p
[root@aaa1 ~]# sysctl -a|grep net.ipv4.tcp_tw
net.ipv4.tcp_tw_reuse =
1
net.ipv4.tcp_tw_recycle = 1
用netstat再观察正常
这里解决问题的关键是如何能够重复利用time_wait的值，我们可以设置时检查一下time和wait的值
#sysctl -a | grep
time | grep wait
net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait =
120
net.ipv4.netfilter.ip_conntrack_tcp_timeout_close_wait =
60
net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait = 120
------------说明：
设置这两个参数： reuse是表示是否允许重新应用处于TIME-WAIT状态的socket用于新的TCP连接； recyse是加速TIME-WAIT sockets回收
