as the <directive module="mpm_common">PidFile</directive> will

    have been removed, you will not be able to use 

    <code>apachectl</code> or <code>httpd</code> to send this signal,</p>

    <note><p>The <code>graceful-stop</code> signal allows you to run multiple

    identically configured instances of <program>httpd</program> at the 

    same time. This is a powerful feature when performing graceful 

    upgrades of Apache, however it can also cause deadlocks and race 

    conditions with some configurations.</p> 

    <p>Care has been taken to ensure that on-disk files

    such as the <directive module="core">Lockfile</directive> and <directive 

    module="mod_cgid">ScriptSock</directive> files contain the server

    PID, and should co-exist without problem. However, if a configuration

    directive, third-party module or persistent CGI utilises any other on-disk 

    lock or  state files; care should be taken to ensure that multiple running 

    instances of <program>httpd</program> do not clobber each others files.</p> 

    <p>You should also be wary of other potential race conditions, such as

    using <program>rotatelogs</program> style piped logging. Multiple running

    instances of <program>rotatelogs</program> attempting to rotate the same

    logfiles at the same time may destroy each other's logfiles.</p></note>

</section>