Web Server Benchmarking with Apache Benchmark Tool: ab

Linux Tutorial – Web Server Benchmarking.

Apache Benchmark Tool: ab

The Apache httpd web server comes with a benchmarking tool to simulate a high load and to gather data for analysis.

ab -n 1000 -c 10 -g test_data_1.txt http://www.your-domain.com/index.html


Option Description
-n number of requests. Default is 1 which is useless.
-c concurrent requests. Default 1
-g GNU plot output. Labels are on first line of output.
-q Suppress progress stattus output to stderr.
-t Time limit. Maximum number of seconds.
-A username:password Specify authentication credentials.
-X proxy[:port] Specify a proxy server.

data file test_data_1.txt.

starttime       seconds ctime   dtime   ttime   wait
Sun Sep 20 00:15:54 2009        1253430954893362        16      808     824 47
Sun Sep 20 00:15:54 2009        1253430954893262        14      957     971 60
Sun Sep 20 00:15:54 2009        1253430954893147        9       1002    1011 62

Console output:

Finished 1000 requests

Server Software:        Apache/2.2.3
Server Hostname:        www.your-domain.com
Server Port:            80

Document Path:          /index.html
Document Length:        83241 bytes

Concurrency Level:      10
Time taken for tests:   14.793312 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      83608000 bytes
HTML transferred:       83241000 bytes
Requests per second:    67.60 [#/sec] (mean)
Time per request:       147.933 [ms] (mean)
Time per request:       14.793 [ms] (mean, across all concurrent requests)
Transfer rate:          5519.25 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0   20 250.2      0    3000
Processing:    53  126  52.7    120     317
Waiting:       19   51  29.5     46     246
Total:         53  147 260.2    120    3305

Percentage of the requests served within a certain time (ms)
  50%    120
  66%    142
  75%    159
  80%    172
  90%    198
  95%    227
  98%    282
  99%    314
 100%   3305 (longest request)

GNU plot to view loading data:

$ gnuplot
gnuplot> set terminal png
gnuplot> set output "ApacheBenchmarkResults.png"
gnuplot> set title "Benchmark from Server X"
gnuplot> set size 1,0.5
gnuplot> set key left top
gnuplot> set xlabel 'request'
gnuplot> set ylabel 'ms'
gnuplot> plot "test_data_1.txt" using 10 with lines title 'Benchmark from Server X'
gnuplot> exit

Apache benchmark server load plot

Benchmarking Tool: httperf

Web performance benchmarking tool httperf. Httperf sends requests to the web server at a specified rate and gathers stats. Increase till one finds the saturation point.


  • Debian: apt-get install httperf

Example usage:

  • Print performance stats for home page of your-domain.com: httperf --hog --server http://www.your-domain.com
  • Create 100 connections at a rate of 10/sec: httperf --hog --server http://www.your-domain.com/ --num-conn 100 --rate 10 --timeout 5
  • Generate 10 sessions at a rate of one session/sec every 2 seconds: httperf --hog --ser=www --wsess=10,5,2 --rate 1 --timeout 5

httperf command line options:

Command Command Description
–hog Use as many TCP ports as necessary to generate stats (else limited to port 1024-5000)
–num-calls Session oriented workloads.
–max-connections=# Limit the number of connections to that specified.
–num-calls=# Specify the number of calls to issue on each connection before closing it.
–server host-name Default localhost. Specify IP address of host name.
–wsess=N1,N2,X Specify session where
N1: number of sessions
N2: number of calls per session
X: delay between calls (sec)
–timeout Stop if there is no response within timeout period.

Benchmarking Tools:



Web Load Calculators:



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