How to Cache Across Multiple Servers

Caching across multiple servers spreads out the database load.

File caching allows you to store files your users might need to access during the time they're on your website or using your Web application. If you dedicate one server for caching, you could be placing an unnecessarily high amount of strain on the server. By distributing the caches, you distribute the load across your servers more evenly, thus giving you more collective computing power you can use for other things.

Instructions

1. Locate the database cache connection initialization in your code, for example:

   define('DBHOSTSERVER', 'dbmaster');

   define('DBUSER', 'username');

   define('DBPASS', 'password');

   $DB_SLAVES = array('dbslaveserver1','dbslaveserver2','dbslaveserver3');

2. Locate the current database that is being used for caching by executing the following code:

   $db->conn_write = mysql_pconnect(DBHOSTSERVER, DBUSER, DBPASS);

   mysql_select_db(DBNAME, $db->conn_write);

3. Pick the slave databases to distribute the caching by using the following code:

   $idx = time () $ count($dbslaveserver1, dbslaveserver2, dbslaveserver3);

   $slave = $dbslaveserver1, dbslaveserver2, dbslaveserver3($idx);

   $db->conn_read = mysql_pconnect($slave, DBUSER, DBPASS);

   mysql_select_db($dbslaveserver1, dbslaveserver2, dbslaveserver3, $db->conn_read);

References

• Real Networks: Multiple Servers
• Cyber Indian: How Multiple Server Hosting Impacts Your Website's Uptime
• Snipe: Quick and Dirty PHP Caching