<p>In seldom cases, you will need to start looking into efficiency issues with Chamilo. This guide is a work in progress intended to help administrators optimize their Chamilo installation.</p>
Set your xcache.ini configuration (/etc/php5/conf.d/xcache.ini) to match your system. For example, you *could* have something like this (intentionally hiding comments here):
<pre>
xcache.shm_scheme = "mmap"
xcache.size = 32M
xcache.count = 2
xcache.slots = 8K
xcache.ttl = 0
xcache.gc_interval = 0
xcache.var_size = 16M
xcache.var_count = 16
xcache.var_slots = 8K
xcache.var_ttl = 60
xcache.var_maxttl = 300
xcache.var_gc_interval = 300
xcache.test = Off
</pre>
xCache will feel useless until you actually start to put some variables in cache. If you're showing the "Who is online" counter, that's one of the best item there is to implement xCache.<br/>
if ((api_get_setting('showonline', 'world') == 'true' AND !$user_id) OR (api_get_setting('showonline', 'users') == 'true' AND $user_id) OR (api_get_setting('showonline', 'course') == 'true' AND $user_id AND $course_id)) {
if ($xc && xcache_isset('campus_chamilo_org_whoisonline_count_simple')) {
Note that, as xCache is a shared caching system, it is very important to prefix your variables with a domain name or some kind of identifier, otherwise it would end up in disaster if you use a shared server for several portals.<br/>
if ((api_get_setting('showonline', 'world') == 'true' AND !$user_id) OR (api_get_setting('showonline', 'users') == 'true' AND $user_id) OR (api_get_setting('showonline', 'course') == 'true' AND $user_id AND $course_id)) {
An optional additional caching mechanism you may use is the realpath_cache_size and realpath_cache_ttl php.ini parameters. See <ahref="http://php.net/manual/en/ini.core.php">the PHP documentation</a> for more details.
If you prefer using <ahref="http://php.net/manual/en/book.apc.php">APC</a>, you can use the same kind of trick as above, just changing the code a little:
<pre>
$xc = function_exists('apc_exists');
$number = 0;
if ((api_get_setting('showonline', 'world') == 'true' AND !$user_id) OR (api_get_setting('showonline', 'users') == 'true' AND $user_id) OR (api_get_setting('showonline', 'course') == 'true' AND $user_id AND $course_id)) {
if ($xc) {
$apc = apc_cache_info(null,true);
$apc_end = $apc['start_time']+$apc['ttl'];
if (apc_exists('my_campus_whoisonline_count_simple') AND (time() < $apc_end) AND apc_fetch('my_campus_whoisonline_count_simple') > 0 ) {
if (apc_exists('my_campus_whoisonline_count_simple_'.$_course['id']) AND (time() < $apc_end) AND apc_fetch('my_campus_whoisonline_count_simple_'.$_course['id']) > 0) {
<p>It is also worth noting that the Université de Genève, Switzerland, observed that the calculation of the total size used by course documents is one of the heaviest queries in Chamilo, so you might want to cache the results of this one as well, using the same technique.</p>
In Chamilo 1.9 in particular, due to the merge of all databases into one, you might experience performance issue if you have many learning paths with many items in them.<br/>
To solve this performance issue, you can execute the following queries manually in your database:<br/>
<pre>
ALTER TABLE lp_item ADD INDEX idx_c_lp_item_cid_lp_id (c_id, lp_id);
ALTER TABLE lp_item_view ADD INDEX idx_c_lp_item_view_cid_lp_view_id_lp_item_id (c_id, lp_view_id, lp_item_id);
</pre>
These will be available in Chamilo 1.10 directly, but we cannot put them into Chamilo 1.9 from now on for organizational reasons.<br/>
Create 10 directories inside the main/upload/users directory (from 0 to 9) and update your admin settings. This has to be done at install & configuration time, otherwise you might loose user data (or have to write a script for data distribution).
Although this will not make your server faster, compressing the pages you are sending to the users will definitely make them feel like your website's responses are a lot faster, and thus increase their well-being when using Chamilo.<br/><br/>
Zlib output compression has to be set at two levels: PHP configuration for PHP pages and Apache for images and CSS.<br/><br/>
To update the PHP configuration (either in php.ini or in your VirtualHost), use the <ahref="http://php.net/manual/en/zlib.configuration.php">zlib.output_compression</a>. If you set this inside your Apache's VirtualHost, you should use the following syntax.
Configuring your Apache server to use output compression is a bit trickier. You have to use <ahref="http://httpd.apache.org/docs/2.2/mod/mod_deflate.html">the mod_deflate module</a> to do it. Your configuration should look like something like this (please read the corresponding documentation before implementing in production).<br/>
Don't have time or resources to optimize your Chamilo installation yourself? Hire an <ahref="http://www.chamilo.org/en/providers">official Chamilo provider</a> and get it sorted out professionally by specialists.
<h2><aname="7.High-numbers-memory"></a>Memory considerations for high numbers of users</h2>
Some administration scripts *have to* handle lists of all users, and this might have a considerable impact on portals with very high numbers of users. For example, the main/admin/add_users_to_session.php script that handles the registration of users into a specific session, if used with the (non-default) full list of users, will devour about 3KB per user, which, for 100,000 users, translates into the need for around 300MB of RAM just to show this page, and to around 3GB for 1,000,000 users.<br/>
This mode is not loaded by default, but could still be selected, leading to a "Fatal error: Allowed memory size ... exhausted" message.<br/>
The only non-scripted solution here is to allow for the corresponding amount of RAM for your PHP configuration (<em>memory_limit = 300M</em>) or your specific VirtualHost if you use mod-php5 (<em>php_value memory_limit 300M</em>).<br/>
Many things in Chamilo are written focusing on the ease of use, even for the administrator. Sometimes, these settings are weighing a little bit more on the system. This is the case, between others, of the mail.conf.php file (being loaded unconditionally) and its CONSTANT "IS_WINDOWS_OS", which is defined by a function call (api_is_windows_os()) at the beginning of main_api.lib.php.
The definition of this constant (which is executed at *every* page load) can easily be avoided, and the only place where it is used inconditionally (mail.conf.php) can be modified to set the line as you expect it (depending on whether you use sendmail/exim or smtp).
<pre>
$platform_email['SMTP_MAILER'] = 'smtp';
</pre>
or
<pre>
$platform_email['SMTP_MAILER'] = 'mail';
</pre>
In fact, the complete loading of mail.conf.php can also be avoided if loaded conditionally (with <i>require_once</i>) when sending an e-mail (which is the only case where it is useful).
<h2><aname="#9.xsendfile"></a>Speeding file downloads with mod_xsendfile</h2>
<p>It might have come to your attention that file downloads through Chamilo might get slow, under default conditions, in particular using Apache 2.</p>
<p>There are several ways to fix this, one of which is removing the .htaccess inside the courses/ directory. This, however, will remove all permissions checks on the files contained in this directory, so... most of the time, not ideal unless your portal is *really* open to the world.</p>
<p>Another technique, revealed to us by <ahref="http://stackoverflow.com/users/46594/virtualblackfox">VirtualBlackFox</a> on <ahref="http://stackoverflow.com/questions/3697748/fastest-way-to-serve-a-file-using-php">this Stackoverflow post</a>, is to use the X-SendFile module for Apache 2.2+ (other web servers might offer other solutions, or avoid the problem initially).</p>
<p>Installing the X-SendFile module will depend on your operating system, but if you use Ubuntu, you'll have to check you are including the "universe" repository inside your packages sources (check /etc/apt/sources.list), then:
<pre>
sudo apt-get update
sudo apt-get install libapache2-mod-xsendfile
sudo service apache2 restart
</pre>
Once you're done with installing, you'll have to configure Chamilo to use it.<br/>
First, edit your VirtualHost or your Apache configuration in general (in Ubuntu, check the /etc/apache2/ or /etc/apache2/sites-available/ folder). This is done by adding the following line inside your configuration, and reloading Apache (example provided on the basis of a virtual host located in /etc/apache2/sites-available/my.chamilo.net.conf) :
<pre>
sudo vim /etc/apache2/sites-available/my.chamilo.net.conf
# add the following line:
X-SendFile on
# exit the file
sudo service apache2 reload
</pre>
Finally, you'll have to got to your Chamilo configuration file, and add the following line at the very bottom of the file main/inc/conf/configuration.php:
Done! Now your downloads should go substantially faster. This is still a feature in observation. We're not sure the benefits are sufficient, so don't hesitate to let us know in <ahref="https://support.chamilo.org/issues/6853">the related issue in Chamilo's tracking system</a>
