Using Memcache Effectively with Drupal 7 Multisite I am setting a hit ratio of 55% on our memcache instance (v1.4.4) and am wondering what can be done to improve the hit ratio. We're in a multisite setup (30+ sites), with two load balanced web servers; there is an instance of memcached on each web server. 

In the settings.php, I have:

$conf['memcache_servers'] = array(
         '11.22.33.44:11211' =&gt; 'default',
         '11.22.33.45:11211' =&gt; 'default',
      );
$conf['memcache_bins'] = array('cache' =&gt; 'default');
$conf['memcache_key_prefix'] = $_SERVER['SERVER_NAME'];


I am looking at using bins to improve hit ratio, but have come across some suggestions that the latest memcache module does this already, but I am unsure as the instructions with the module contain directions on setting up bins. 

If bins are they way to go, how do you determine what (table?) needs to have its own bin? These are the cache tables that I have in my sites:

cache
cache_admin_menu (empty)
cache_block (empty)
cache_bootstrap
cache_field
cache_filter (empty)
cache_form (empty)
cache_image (empty)
cache_media_xml (empty)
cache_menu
cache_page (empty)
cache_path (empty)
cache_token (empty)
cache_update (empty)
cache_views
cache_views_data (empty)
ctools_css_cache (empty)
ctools_object_cache (empty)


In addition to bins, what else can I be doing to improve memcached usage?

Many thanks!
After much research, here is what has helped our hit ratio and memcached usage:


Upgraded memcached to 1.4.10 (the latest version with performance improvements)
Enabled binary format and compression
Use the default for bins


Our memcached conf in settings.php looks something like this now:

$conf['memcache_bins'] = array('cache' =&gt; 'default');
$conf['memcache_options'] = array(
  Memcached::OPT_COMPRESSION =&gt; TRUE,
  Memcached::OPT_BINARY_PROTOCOL =&gt; TRUE,
  );
$conf['memcache_persistent'] = TRUE;
$conf['memcache_key_prefix'] = $_SERVER['SERVER_NAME'];


Biggest Gains

The biggest gain for us was enabling compression, even though the documentations states that it increases CPU cycles. We have 4 CPUs allocated to our VM, and have not noticed a difference. Time for memcached calls went from ~1250ms to ~150ms (obtained from NewRelic) for creating a piece of content (custom Article in our case).  

Hit Ratio

Our hit ratio is now ~70% -- much better than 55% earlier, but not quiet the 90%+ that some have reported ... the quest continues (-:

Hopefully this helps someone else. If you come across other improvements or have corrections/suggestions, please post comments or answers. 

Update -- Version of memcahe module

We went from version 1.0-beta4 to 1.0 and our hit ratio now is 87% . I had to restart memcached as hit ratio wasn't going past 70%. We have 64MB allocated to memcached at the moment, so this was not a big deal for us.