Giới thiệu 3 cách nâng cao để boost Drupal performance

Drupal is powerful CMS which used to built many high traffic websites. However, the performance of Drupal always a concern for many users. In my pervious article introduced 4 simple steps to boost Drupal performance for many anonymous visit. However, if your find those are not enoguht, there are 3 extra tricks which can further boost Drupal performance.

1. CacheRouter

CacheRouter is a module which can replace default Drupal caching mechanisms which allowing you to use individual cache tables for specific cache technology.

And CacheRouter fully support the following technologies:

• APC
• Database
• eAccelerator
• File
• Memcache
• XCache

To enable this, there are two simple steps:

i ) Enable the module in admin panel

Your should go to "http://yourdomain.com/admin/build/modules" to enable the CacheRouter module

ii) Configurate settings.php

First, you have to inform Drupal to use your common caching system by adding the follow line in setting.php.

     $conf['cache_inc'] = './sites/all/modules/contrib/cacherouter/cacherouter.inc';
     $conf['cacherouter'] = array(
           'default' => array(
           'engine' => 'db',
           'servers' => array(),
           'shared' => TRUE,
           'prefix' => '',
           'path' => 'sites/default/files/filecache',
           'static' => FALSE,
           'fast_cache' => TRUE,
         ),
     );

The above setting which tell Drupal to user CacheRouter to user for all cache bins and store the cache content as files. The cache    store in 'sites/default/files/filecache' directory.

Discuss about Drupal cache tables

There are several database tables that shipped with Drupal 6 for caching purpose:

• cache - Used for all common cache purpose. This is a default cache bin for Drupal.
• cache_block - Used for storing block's cache.
• cache_filter - Used for storing filtered input.
• cache_form - Used for stroing forms.
• cache_menu - Used for storing assembled and processed menu.
• cache_page - Used to store cached pages.
• cache_update - Used to store Drupal, modules and themes update information if "Update status" enabled.

Other than default cache tables, there are some common cache tables used by those widely used modules:

• CCK - cache_content - Used to store cck-related information.
• Views - cache_views - Used to store view object and cache_views_data which storing query results and those rendered output.

Now, we have a brief understand how Drupal cache the data into which database tables. Here, we can do some extra cache configuration:

   $conf['cacherouter'] = array(

        'default' => array(

        'engine' => 'file',

        'servers' => array(),

        'shared' => TRUE,

        'prefix' => '',

        'path' => 'sites/default/files/filecache',

        'static' => FALSE,

        'fast_cache' => TRUE

   ),

   'cache_menu' => array(

        'engine' => 'db',

        'servers' => array(),

        'shared' => TRUE,

        'prefix' => '',

        'path' => '',

        'static' => FALSE,

        'fast_cache' => TRUE
    )
);

We can specify different cache bins use different kind of cahce mechanism. Like the code on above which specify "cache_menu" use db to cache.

2. Use Elysia Cron instead

Drupal's cron is an useful tool which can run heavy tasks in background through hook_cron. However, there are some limitations:

• All cron job for all modules are run at the same time, in sequence, alphabetically or according to module weight.
• If cron of one module get stuck, the rest of the modules would not be executed until cron run next time.
• Limited information on which cron hook takes most time or which cron hook have problem get stuck.

By using Elysia Cron which allow you with great flexibility to manage your cron tasks, such as: reorder cron tasks, disable cron tasks. It also give you information on which cron task consumes most of the time. For more information, visit the module page here.

3. Use Memcache with Drupal

To further optimize, there is one more option is to use Memcahe.  It used RAM for storing data which is extremely fast. And we can configure cache bins to storu in memory. In order to do this, you should make sure your server installed with Memcached caching. Once your server installed, we can configurate Drupal use Memcache by adjusting configuration of CacheRouter.

   $conf['cacherouter'] = array(
       'default' => array(
       'engine' => 'memcache',
       'servers' => array('127.0.0.1:11211', '127.0.0.1:11212'),
       'shared' => TRUE,
       'prefix' => 'your_site_name_prefix',
       'path' => '',
       'static' => FALSE,
       'fast_cache' => TRUE
       )
   );

Here, we configurated Drupal to use memcached as backend with 2 instances ('127.0.0.1:11211', '127.0.0.1:11212'). And you can configurate the 2 instances located at two different IPs and ports, such as: '192.168.1.100:11211', '192.168.1.101:11212' . Prefix is used to separate different caches from each others. For instance - you may have several Drupal projects, which may use same  memcached instances.

In most cases, you need to configurate the size of bins and instances:

default:  For cache, cache_views, cache_update. 256 MBytes in size.

menu:    For cache_menu bin. 64 MBytes in size.

content: For cache_views_data, cache_content, cache_page bins. 64 MBytes in size.

block:     For cache_block bin. 64 MBytes in size.

filter:      For cache_filter bin. 64 MBytes in size.

form:      For cache_form bin. 64 MBytes in size.

Conclude

CacheRouter is a very useful module which allow Drupal to work with various kinds of cahching mechanism, such as: file base, db, memcache ... etc. However, compare CacheRouter with Boost module, it require more configuration and settings. However, it do provide more flexibility to optimize Drupal performance which is a very useful module to optimize performance for high traffic web site.