El comando ab

La utilidad ab (Apache Benchmark) sirve para hacer pruebas de carga a un servidor apache. Es un programa que forma parte del apaquete apache2-utils.

Veamos un ejemplo::

ab -n 1000 -c 5 -k http://localhost/

El anterior comando simula 5 usuarios al mismo tiempo ahciendo 1000 peticiones al servidor web del localhost. La opción -k (keep_alive) habilita la opción de no cerrar la sesión HTTP. Veamos los resultados de este comando::

Benchmarking localhost (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
Completed 900 requests
Completed 1000 requests
Finished 1000 requests	


Server Software:        Apache/2.2.16
Server Hostname:        localhost
Server Port:            80	

Document Path:          /
Document Length:        42587 bytes	

Concurrency Level:      5
Time taken for tests:   0.140 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Keep-Alive requests:    995
Total transferred:      42903740 bytes
HTML transferred:       42587000 bytes
Requests per second:    7124.44 [#/sec] (mean)
Time per request:       0.702 [ms] (mean)
Time per request:       0.140 [ms] (mean, across all concurrent requests)
Transfer rate:          298500.90 [Kbytes/sec] received	

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       3
Processing:     0    1   0.1      1       3
Waiting:        0    0   0.2      0       2
Total:          0    1   0.2      1       3	

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      1
  80%      1
  90%      1
  95%      1
  98%      1
  99%      1
 100%      3 (longest request)

Tenemos otra opción donde indicamos el tiempo que va a durar la prueba y el nivel de concurrencia, sería de la siguiente forma:

ab -t 10 -c 5 -k http://localhost/

En este caso se va a realizar la prueba durante 10 segundos.