[Safe Communication] Stress test using Apache's ab tool

ab command principle
Apache's ab command simulates multi-threaded concurrent requests to test server load pressure, as well as other web servers such as nginx, lighthttp, and IIS.
Apache附带的ab工具（使用的PHP环境是WAMP集成环境，ab工具位于D:wampinapacheApache2.2.21in）非常容易使用。 The ab command has very low requirements for the computer that issues the load, and it will not take up a lot of CPU or too much memory, but it will cause a huge load on the target server, so it is a necessary medicine for some DDOS attacks, suitable for all ages. You must also be cautious when using it yourself. Otherwise, too much load at one time will cause the target server to die directly due to memory exhaustion and have to be hard restarted, which is not worth the loss.

In the case of insufficient bandwidth, it is best to test locally, and it is recommended to use another or multiple servers on the intranet to test through the intranet, so that the data obtained will be much more accurate. Stress testing web servers remotely often results ineffective (due to excessive network latency or insufficient bandwidth)

Download and Install:
http://mirror.bit.edu.cn/apache//httpd/binaries/win32/?C=M;O=A
Find httpd-2.2.21-win32-x86-no_ssl.msi  

Parameter Documentation:
http://httpd.apache.org/docs/2.2/programs/ab.html

Operation:
On Windows, open the cmd command line window and locate it to the bin directory of the apache installation directory
cd C:Program Files (x86)Apache Software FoundationApache2.2in

Type the command:
ab -n 800 -c 800  http://192.168.0.10/
(-n makes 800 requests, -c simulates 800 concurrency, equivalent to 800 people visiting at the same time, followed by the test url)

ab -t 60 -c 100 http://192.168.0.10/
Send requests within 60 seconds, 100 requests at a time.
  
//如果需要在url中带参数，这样做
ab -t 60 -c 100 -T "text/plain" -p p.txt http://192.168.0.10/hello.html
p.txt is and ab.exe in a directory
p.txt, you can write parameters such as p=wdp&fq=78

Explanation of the resulting parameters:
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.0.10 (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Finished 800 requests

Server Software: Microsoft-HTTPAPI/2.0 indicates the name of the web server software being tested
Server Hostname: 192.168.0.10 Indicates the hostname of the URL of the request
Server Port: 80 indicates the listening port of the web server software being tested

Document Path: / represents the root absolute path in the URL of the request, and we can generally understand the type of request by the suffix name of the file
Document Length: 315 bytes represents the body length of the HTTP response data

Concurrency Level: 800 represents the number of concurrent users, which is one of the parameters we set
Time taken for tests: 0.914 seconds The time it takes for all of these requests to complete processing
Complete requests: 800 completed requests
Failed requests: 0 The number of failed requests
Write errors:           0               
Non-2xx responses:      800
Total transferred: 393600 bytes Total network transfer
HTML transferred: 252000 bytes HTML content transferred
Requests per second: 875.22 [#/sec] (mean) Throughput - Requests per second
Time per request: 914.052 [ms] (mean) The time it takes for the server to respond to the request and respond to the page
Time per request: 1.143 [ms] (mean, across all concurrent requests) The average time consumed per concurrent request
Transfer rate: 420.52 [Kbytes/sec] received average traffic per second on the network, which can help rule out the problem of excessive network traffic causing long response times

Breakdown of time consumed on the network:
Connection Times (ms)  min  mean[+/-sd] median   max
Connect:        0    1   0.5      1       3
Processing:   245  534 125.2    570     682
Waiting:       11  386 189.1    409     669
Total:        246  535 125.0    571     684

The response of all requests throughout the scenario. In a scenario, each request has a response time
50% of these users have a response time of less than 571 milliseconds
80% of users have a response time of less than 652 ms
The maximum response time is less than 684 ms
Percentage of the requests served within a certain time (ms)
  50%    571
  66%    627
  75%    646
  80%    652
  90%    666
  95%    677
  98%    681
  99%    682
100%    684 (longest request)

This part of the data is used to describe the distribution of each request processing time, for example, in the above test, 80% of the request processing time does not exceed 6ms, this processing time refers to the previous Time per request, that is, for a single user, the average processing time per request.