Several NFS folders for one Drupal instance
ini_set('opcache.validate_timestamps', FALSE);


Then when you want to push a code change out run

opcache_reset();


or restart the Apache process.

If you're working on a set of files you can use opcache_invalidate() to check if those files need to be recompiled.

// http://stackoverflow.com/questions/24783862/php-recursively-list-all-files-in-directory
function get_dir_contents($dir, &amp;$results = array()){
  $files = scandir($dir);

  foreach($files as $key =&gt; $value){
    $path = realpath($dir. DIRECTORY_SEPARATOR. $value);
    if (!is_dir($path)) {
      $results[] = $path;
    }
    elseif (is_dir($path) &amp;&amp; $value != "." &amp;&amp; $value != "..") {
      get_dir_contents($path, $results);
      $results[] = $path;
    }
  }

  return $results;
}

// https://api.drupal.org/api/drupal/core!lib!Drupal!Component!Utility!OpCodeCache.php/function/OpCodeCache%3A%3Ainvalidate/8
function invalidate_opcodecache($pathname) {
  clearstatcache(TRUE, $pathname);

  // Check if the Zend OPcache is enabled and if so invalidate the file.
  if (function_exists('opcache_invalidate')) {
    opcache_invalidate($pathname, TRUE);
  }
  // If apcu extension is enabled in PHP 5.5 or greater it emulates apc.
  // This is to provide an easy upgrade path if you are using apc's user
  // caching however the emulation does not extend to opcode caching.
  // Therefore we need to check if the function exists as well.
  if (extension_loaded('apc') &amp;&amp; function_exists('apc_delete_file')) {
    // apc_delete_file() throws a PHP warning in case the specified file was
    // not compiled yet.
    // @see http://php.net/manual/en/function.apc-delete-file.php
    @apc_delete_file($pathname);
  }
}


$file_path = 'sites/all/modules/custom';
$files = get_dir_contents($file_path);
foreach ($files as $pathname) {
  invalidate_opcodecache($pathname);
}
$file_path = 'sites/all/themes/custom';
$files = get_dir_contents($file_path);
foreach ($files as $pathname) {
  invalidate_opcodecache($pathname);
}


Put this code in your settings.php file. 

If using APC the info for that is located here: Best APC settings to reduce page execution time

And apache: Adding .htaccess within httpd.conf correctly

Also see: First page load/execution slow, login slower Drupal 7