ab is erroring out with apr_socket_recv: Connection refused (61)

I found using 127.0.0.1 rather than localhost worked:

ab -n 10 -c 1 http://127.0.0.1:8090/

Update: May have been a bug in ab: https://groups.google.com/forum/#!msg/nodejs/TZU5H7MdoII/yivu0d4LMaAJ

Another related bug that is still present in ab (apache-2.4.29) is that it takes just the first result from getaddrinfo. It's probably this bug that is mentioned by Jürgen Strobel in a comment. Let's say you have /etc/hosts that goes like this:

127.0.0.1   localhost.localdomain   localhost
::1     localhost.localdomain   localhost

The first result returned by getaddrinfo for localhost is ::1. So ab tries to connect over IPv6 and fails. The workaround is to use 127.0.0.1: ab -n 10 127.0.0.1/. Or reorder the lines. Though, in my case it says:

Benchmarking localhost (be patient)...apr_socket_recv: Connection refused (111)

New version's apache have fix the issue. Only have to rebuild ab.

Try to download latest package from http://archive.apache.org/dist/

Have to patch apache and build a new ab.

$ wget http://archive.apache.org/dist/httpd/httpd-2.3.16-beta.tar.bz2
$ tar jxvf httpd-2.3.16-beta.tar.bz2 
$ cd httpd-2.3.16-beta
$ ./configure

Only have to build ab, which located in support folder.

$ cd support
$ make
...
$ ./ab -n 10 -c 1 http://localhost:8090/

If your apache is very old, then patch it and build as above.

$ wget https://www.rtfm.ro/download/patches/ab.patch --no-check-certificate
$ patch -p0 < ./ab.patch

Done.

add the -r option which means Don't exit on socket receive errors. At times you might change the default ulimit size value. ab -r -n 10 -c 1 http://localhost:8090/