我们在AWS上有很少的EC2服务器，但我们注意到一个特殊的服务器奇怪的问题。首先，SSH需要几十秒，但只是间歇性地发生。其次，获取服务器的请求也需要几十秒，但它又间歇性地发生。我们检查了服务器上的统计数据，一切看起来都很好。 CPU平均值约为7％，25GB的免费内存。 以下是来自ss -s的回复：
Total: 2553 (kernel 0)
TCP: 12015 (estab 2342, closed 9189, orphaned 478, synrecv 0, timewait 9188/0), ports 0
Transport Total IP IPv6
* 0 - -
RAW 0 0 0
UDP 4 4 0
TCP 2826 2765 61
INET 2830 2769 61
FRAG 0 0 0
当前连接状态的细分：
1 established)
1 Foreign
6 LISTEN
62 LAST_ACK
136 SYN_RECV
155 CLOSING
251 FIN_WAIT1
1078 FIN_WAIT2
2197 ESTABLISHED
8229 TIME_WAIT
我们已经排除了DNS问题，因为当我们尝试通过它的主机名或IP地址访问它时会发生这种情况。该服务器前面没有负载均衡器。我们确实使用Route53进行路由，但我没有看到任何问题。
使用AB来获取请求： 运行＃1
Server Software: nginx/1.6.1
Server Hostname: my.hidden.com
Server Port: 443
SSL/TLS Protocol: TLSv1,DHE-RSA-AES256-SHA,2048,256
Document Path: /debug
Document Length: 43 bytes
Concurrency Level: 1
Time taken for tests: 104.415 seconds
Complete requests: 500
Failed requests: 0
Total transferred: 162304 bytes
HTML transferred: 21500 bytes
Requests per second: 4.79 [#/sec] (mean)
Time per request: 208.829 [ms] (mean)
Time per request: 208.829 [ms] (mean, across all concurrent requests)
Transfer rate: 1.52 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 134 160 35.7 154 709
Processing: 39 49 8.2 48 127
Waiting: 39 49 8.2 48 127
Total: 178 209 38.6 203 809
Percentage of the requests served within a certain time (ms)
50% 203
66% 209
75% 212
80% 215
90% 225
95% 244
98% 273
99% 302
100% 809 (longest request)
运行＃2
Server Software: nginx/1.6.1
Server Hostname: my.hidden.com
Server Port: 443
SSL/TLS Protocol: TLSv1,DHE-RSA-AES256-SHA,2048,256
Document Path: /debug
Document Length: 43 bytes
Concurrency Level: 1
Time taken for tests: 515.608 seconds
Complete requests: 500
Failed requests: 0
Total transferred: 162284 bytes
HTML transferred: 21500 bytes
Requests per second: 0.97 [#/sec] (mean)
Time per request: 1031.216 [ms] (mean)
Time per request: 1031.216 [ms] (mean, across all concurrent requests)
Transfer rate: 0.31 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 136 980 1251.8 164 5575
Processing: 39 51 33.0 48 730
Waiting: 39 51 33.0 48 730
Total: 180 1031 1258.7 216 6306
Percentage of the requests served within a certain time (ms)
50% 216
66% 243
75% 2839
80% 2850
90% 2874
95% 2903
98% 2935
99% 2992
100% 6306 (longest request)
运行＃3
Server Software: nginx/1.6.1
Server Hostname: my.hidden.com
Server Port: 443
SSL/TLS Protocol: TLSv1,DHE-RSA-AES256-SHA,2048,256
Document Path: /debug
Document Length: 43 bytes
Concurrency Level: 1
Time taken for tests: 417.639 seconds
Complete requests: 500
Failed requests: 0
Total transferred: 162320 bytes
HTML transferred: 21500 bytes
Requests per second: 1.20 [#/sec] (mean)
Time per request: 835.279 [ms] (mean)
Time per request: 835.279 [ms] (mean, across all concurrent requests)
Transfer rate: 0.38 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 137 781 1140.0 162 5053
Processing: 38 54 56.6 49 1281
Waiting: 38 54 56.6 49 1281
Total: 179 835 1141.2 213 5104
Percentage of the requests served within a certain time (ms)
50% 213
66% 233
75% 334
80% 2835
90% 2872
95% 2915
98% 3030
99% 3137
100% 5104 (longest request)
运行＃4
Server Software: nginx/1.6.1
Server Hostname: my.hidden.com
Server Port: 443
SSL/TLS Protocol: TLSv1,DHE-RSA-AES256-SHA,2048,256
Document Path: /debug
Document Length: 43 bytes
Concurrency Level: 1
Time taken for tests: 104.806 seconds
Complete requests: 500
Failed requests: 0
Total transferred: 162250 bytes
HTML transferred: 21500 bytes
Requests per second: 4.77 [#/sec] (mean)
Time per request: 209.611 [ms] (mean)
Time per request: 209.611 [ms] (mean, across all concurrent requests)
Transfer rate: 1.51 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 135 160 13.8 157 227
Processing: 39 50 8.8 48 159
Waiting: 39 50 8.8 48 159
Total: 179 209 17.7 206 331
Percentage of the requests served within a certain time (ms)
50% 206
66% 212
75% 216
80% 219
90% 230
95% 240
98% 266
99% 275
100% 331 (longest request)
运行＃5
Server Software: nginx/1.6.1
Server Hostname: my.hidden.com
Server Port: 443
SSL/TLS Protocol: TLSv1,DHE-RSA-AES256-SHA,2048,256
Document Path: /debug
Document Length: 43 bytes
Concurrency Level: 1
Time taken for tests: 110.983 seconds
Complete requests: 500
Failed requests: 0
Total transferred: 162282 bytes
HTML transferred: 21500 bytes
Requests per second: 4.51 [#/sec] (mean)
Time per request: 221.967 [ms] (mean)
Time per request: 221.967 [ms] (mean, across all concurrent requests)
Transfer rate: 1.43 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 132 170 149.3 159 3460
Processing: 38 52 25.8 49 589
Waiting: 38 52 25.8 49 589
Total: 177 222 152.6 208 3532
Percentage of the requests served within a certain time (ms)
50% 208
66% 217
75% 222
80% 227
90% 240
95% 257
98% 282
99% 336
100% 3532 (longest request)