Manual Page: ab
ab - Apache HTTP server benchmarking tool
ab [ -k ] [ -i ] [ -n requests ] [ -t timelimit ] [ -c con-
currency ] [ -p POST file ] [ -A Authenticate
username:password ] [ -P Proxy Authenticate
username:password ] [ -H Custom header ] [ -C Cookie
name=value ] [ -T content-type ] [ -v verbosity ] [ -w
output HTML ] [ -x <table> attributes ] [ -X proxy[:port] ]
[ -y <tr> attributes ] [ -z <td> attributes ]
ab [ -V ] [ -h ]
ab is a tool for benchmarking the performance of your Apache
HyperText Transfer Protocol (HTTP) server. It does this by
giving you an indication of how many requests per second
your Apache installation can serve.
-k Enable the HTTP KeepAlive feature; that is, per-
form multiple requests within one HTTP session.
Default is no KeepAlive.
-i Use an HTTP 'HEAD' instead of the GET method.
Cannot be mixed with POST.
-n requests The number of requests to perform for the bench-
marking session. The default is to perform just
one single request, which will not give
representative benchmarking results.
The number of seconds to spend benchmarking.
Using this option automatically set the number
of requests for the benchmarking session to
50000. Use this to benchmark the server for a
fixed period of time. By default, there is no
The number of simultaneous requests to perform.
The default is to perform one HTTP request at a
time, that is, no concurrency.
-p POST file
A file containing data that the program will
send to the Apache server in any HTTP POST
requests. The contents of the file should look
name=value&something=other, with special
characters URL encoded.
-A Authorization username:password
Supply Basic Authentication credentials to the
server. The username and password are separated
by a single ':', and sent as uuencoded data.
The string is sent regardless of whether the
server needs it; that is, has sent a 401 Authen-
-P Proxy-Authorization username:password
Supply Basic Authentication credentials to a
proxy en-route. The username and password are
separated by a single ':', and sent as uuencoded
data. The string is sent regardless of whether
the proxy needs it; that is, has sent a 407
Proxy authentication needed.
-C Cookie name=value
Add a 'Cookie:' line to the request. The argu-
ment is typically a 'name=value' pair. This
option may be repeated.
-H Header string
Append extra headers to the request. The argu-
ment is typically in the form of a valid header
line, usually a colon separated field value
pair, for example, 'Accept-Encoding:
The content-type header to use for POST data.
-v Sets the verbosity level. Level 4 and above
prints information on headers, level 3 and above
prints response codes (for example, 404, 200),
and level 2 and above prints warnings and infor-
-w Print out results in HTML tables. The default
table is two columns wide, with a white back-
The string to use as attributes for <table>.
Attributes are inserted <table here >
Use the specified proxy server, running on the
The string to use as attributes for <tr>.
The string to use as attributes for <td>.
-V Display the version number and exit.
-h Display usage information.
There are various statically declared buffers of fixed
length. Combined with inefficient parsing of the command
line arguments, the response headers from the server, and
other external inputs, these buffers might overflow.
Ab does not implement HTTP/1.x fully; instead, it only
accepts some 'expected' forms of responses.
The rather heavy use of strstr(3) by the program may skew
performance results, since it uses significant CPU
resources. Make sure that performance limits are not hit by
ab before your server's limit is reached.