利用tcpcopy，对nginx进行压力测试，效果见正文（注意用的是tcpcopy 0.5以下的版本）

从上午10：41分开始试验，一直到18：17，7个半小时左右。

从4台nginx服务器拷贝流量到测试服务器，由于lvs有两个虚拟ip，在在线服务器执行命令如下：

[root@bgp176-141 work]# ./tcpcopy xxx.xxx.xxx.140 80  xxx.xxx.xxx.148 18080

root@bgp176-142 work]#  ./tcpcopy xxx.xxx.xxx.137 80 xxx.xxx.xxx.148 18080
[root@bgp176-143 work]# ./tcpcopy xxx.xxx.xxx.140 80 xxx.xxx.xxx.148 18080

[root@bgp176-144 work]# ./tcpcopy xxx.xxx.xxx.137 80 xxx.xxx.xxx.148 18080  

上述4台服务器所copy的流量大概是在线服务器的2倍流量

测试服务器中途遇到ip queue full的情况，修改ip queue length后就没有再出现

echo 4096 > /proc/sys/net/ipv4/ip_queue_maxlen

cat /var/log/messages部分数据如下：

Nov  2 10:45:13 bgp176-148 kernel: printk: 118 messages suppressed.
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243413
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243414
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243415
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243416
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243417
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243418
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243419
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243420
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243421
Nov  2 10:45:13 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243422
Nov  2 10:56:53 bgp176-148 kernel: printk: 274 messages suppressed.
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243697
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243698
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243699
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243700
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243701
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243702
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243703
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243704
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243705
Nov  2 10:56:53 bgp176-148 kernel: ip_queue: full at 1024 entries, dropping packets(s). Dropped: 2243706
Nov  2 11:18:42 bgp176-148 ntpd[1851]: time reset +0.212364 s
Nov  2 11:22:56 bgp176-148 ntpd[1851]: synchronized to LOCAL(0), stratum 10
Nov  2 11:23:33 bgp176-148 ntpd[1851]: synchronized to 220.181.28.157, stratum 2
Nov  2 11:27:15 bgp176-148 ntpd[1851]: synchronized to 122.226.192.4, stratum 2

执行到18点多的时候，我们来分析使用情况

root@bgp176-148 logs]# date

Wed Nov  2 18:17:02 CST 2011

[root@bgp176-148 logs]# ps aux|grep interception

root      7855 34.6  4.4  94052 92708 pts/1    S+   10:40 158:09 ./interception

[wangbin@bgp176-141 logs]$ ps aux|grep tcpcopy
wangbin   9041  0.0  0.0  61188   732 pts/1    S+   18:17   0:00 grep tcpcopy

root     27198 21.3  0.7  40952 28068 pts/0    Rl+  10:41  97:24 ./tcpcopy xxx.xxx.xxx.140 80 xxx.xxx.xxx.148 18080

测试服务器数据如下：

 7830 adrun     15   0 22340  18m  932 S 30.8  0.9 202:34.59 nginx                                                                  
 7832 adrun     15   0 22456  19m  932 S 30.8  0.9 206:58.98 nginx                                                                  
 7829 adrun     15   0 21848  18m  932 S 29.7  0.9 181:29.62 nginx                                                                  
 7831 adrun     15   0 22084  18m  932 S 27.4  0.9 192:06.58 nginx                                                                  
 7855 root      15   0 94052  90m  400 S 25.1  4.5 159:41.30 interception                                                           
 5363 root      18   0 37764  23m  744 S 17.1  1.2 155:03.92 asyn_server

-rw-r--r-- 1 root  root  25393322281 Nov  2 18:18 access.log

我们分析请求处理情况：

[wangbin@bgp176-141 logs]$ grep '2011:18:35' access.log |wc -l
69737

[root@bgp176-148 logs]# tail -n 1000000 access.log |grep '2011:18:35' |wc -l    
139653
2倍流量=69737×2=139474，接近在线流量的2倍

中间的情况如下：

[root@bgp176-148 logs]# tail -n 1000000 access.log |grep '2011:13:36' |wc -l
191913
[root@bgp176-148 logs]# tail -n 1000000 access.log |grep '2011:13:37' |wc -l
190548
[root@bgp176-148 logs]# tail -n 1000000 access.log |grep '2011:13:44' |wc -l  
190721
[root@bgp176-148 logs]# tail -n 1000000 access.log |grep '2011:13:47' |wc -l  
189788


[wangbin@bgp176-141 logs]$ grep '2011:13:37' access.log |wc -l
97498
[wangbin@bgp176-141 logs]$ grep '2011:13:36' access.log |wc -l
97693
[wangbin@bgp176-141 logs]$ grep '2011:13:44' access.log |wc -l  
94891
[wangbin@bgp176-141 logs]$ grep '2011:13:47' access.log |wc -l
94464
两倍=97498×2=194996
两倍=97693×2=195386
两倍=94891×2=189782
两倍=94464×2=188928

我们可以得出结论，通过tcpcopy，nginx目前能够承受2倍的在线压力