You will need a third-party program called PsExec to do this. Otherwise you won't be able to start a background process using Ruby on Windows.
First of all download PsExec here. Unpack (at least) psexec.exe
and run it once manually - you have to agree to the license :-/.
After that add the following line to script/server
of your Rails app:
system 'PATH_TO_PSEXEC/psexec -d rake.bat'
Now you create the rake.bat
with the commands to run in parallel to your server. Put the file with the following contents into your Rails app's root directory.
rake thinking_sphinx:start
This line should do the trick, but it may fail e.g. when NetBeans' JRuby version differs from Ruby installed on your host. Or if Ruby isn't installed at all. In that case you should call rake with the complete path of JRuby:
"PATH_TO_NETBEANS/ruby2/jruby-1.2.0/bin/jruby" "PATH_TO_NETBEANS/ruby2/jruby-1.2.0/bin/rake" thinking_sphinx:start
When you start the server now, an additional Windows command-line pops up with the running rake task.
Needless to say that you shouldn't add the code to script/server
on your production server.