An indication of expected performance

I've done a very quick performance test, just to give an idea of what you might expect when serving cached pages (anonymous users) - I hope this is useful to someone:

Requests served per second measured using Apache ab

• ab command used: ab -H "Accept-Encoding: gzip" -n1600 -c8 http://localhost/node/20
• An almost minimal D7 installation but with multi-language (Internationalisation) activated
• Unloaded 2.2 GHz dual processor, 4GB RAM.

Note: It's important to include -H "Accept-Encoding: gzip" because otherwise results are slower due to the time taken for the server to uncompress gzip-compressed content before returning it.

To repeat, this was just a quick test and probably not very representative of real-world results, but hopefully better than nothing.

Here's what I put in my settings.php to quickly change configuration (change 1 to 0 where required):

if (1) {
  $conf['cache_backends'] = array('sites/all/modules/apc/drupal_apc_cache.inc');

  if (1) {
    // Use APC by default (cache everything.)
    $conf['cache_default_class'] = 'DrupalAPCCache';
    if (1) {
      // Page cache without database and module hooks (approx twice as fast.)
      $conf['page_cache_invoke_hooks'] = FALSE;
      $conf['page_cache_without_database'] = TRUE;
    }
  }
  else {
    // Use APC for "cache" and "bootstrap" only.
    $conf['cache_class_cache'] = 'DrupalAPCCache';
    $conf['cache_class_cache_bootstrap'] = 'DrupalAPCCache';
  }
}