Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Getting this result from ab:

Concurrency Level:      10000

Time taken for tests:   69.153 seconds

Complete requests:      30000

Failed requests:        10379  

(Connect: 0, Receive: 3424, Length: 3531, Exceptions: 3424)

Write errors:           0

Total transferred:      48414203 bytes

HTML transferred:       41042477 bytes

Requests per second:    433.82

[#/sec] (mean)

What does Receive and Exceptions mean EXACTLY. Thanks.

share|improve this question
up vote 2 down vote accepted

From ,

Failed requests
The number of requests that were considered a failure. If the number is greater
than zero,another line will be printed showing the numer of requests that
failed due to connecting, reading, incorrect content length, or exceptions.

If you are testing a "dynamic" page, then the conten-length will change and may result in a failure. Examples are ads or images or varying results on a page.

Exceptions, im guessing, are just exceptions thrown by the application on the page.

Your failure rate could be high because your backend application may not be able to withstand the load or the connections.

UPDATE: From ab source code, Receive (count of err_recv) means

/* catch legitimate fatal apr_socket_recv errors */
    else if (status != APR_SUCCESS) {
        if (recverrok) {
            if (verbosity >= 1) {
                char buf[120];
                fprintf(stderr,"%s: %s (%d)\n", "apr_socket_recv", apr_strerror(status, buf, sizeof buf), status);

This basically means, your apache/webserver had trouble with the packets sent by ab. This could be because of many things -- network, apache too busy ... When you ran the tests, did you see any errors in apache/webserver logs? specifically, connection reset or timed out?

share|improve this answer
Yeah. The length errors I'm not worried about. It's the Receive and Exceptions. – joedevon Aug 19 '12 at 13:45
Thanks.... "When you ran the tests, did you see any errors in apache logs? specifically, connection reset or timed out?" Yes, tons – joedevon Aug 19 '12 at 15:49
Then those are probably the receive errors. Looks like your server was too busy processing requests. – Chida Aug 19 '12 at 16:39

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.