Load Balance & Fail Over PDO mysql Connection

PDOfailover.php

<?php

$ran = rand(1,10);
if ($ran < 5) {
$host = '10.0.0.2';
$backup = '10.0.0.3:3306';
} else {
$host = '10.0.0.3:3306';
$backup = '10.0.0.2:3306';
}


	// UTF-8 is a character encoding scheme that allows you to conveniently store 
    // a wide varienty of special characters, like ¢ or €, in your database. 
    // By passing the following $options array to the database connection code we 
    // are telling the MySQL server that we want to communicate with it using UTF-8 
    // See Wikipedia for more information on UTF-8: 
    // http://en.wikipedia.org/wiki/UTF-8 
    $options = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'); 
     
    // A try/catch statement is a common method of error handling in object oriented code. 
    // First, PHP executes the code within the try block.  If at any time it encounters an 
    // error while executing that code, it stops immediately and jumps down to the 
    // catch block.  For more detailed information on exceptions and try/catch blocks: 
    // http://us2.php.net/manual/en/language.exceptions.php 
    try 
    { 
        // This statement opens a connection to your database using the PDO library 
        // PDO is designed to provide a flexible interface between PHP and many 
        // different types of database servers.  For more information on PDO: 
        // http://us2.php.net/manual/en/class.pdo.php 
        $db = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $username, $password, $options); 
    } 
    catch(PDOException $ex) 
    { 
        // If an error occurs while opening a connection to your database, it will 
        // be trapped here.  The script will output an error and stop executing. 
        // Note: On a production website, you should not output $ex->getMessage(). 
        // It may provide an attacker with helpful information about your code 
        // (like your database username and password). 
		$db = new PDO("mysql:host={$backup};dbname={$dbname};charset=utf8", $username, $password, $options); or die('Could not connect to the database server!'); OR
        die("Failed to connect to the database: " . $ex->getMessage()); 
    } 
     
    // This statement configures PDO to throw an exception when it encounters 
    // an error.  This allows us to use try/catch blocks to trap database errors. 
    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
     
    // This statement configures PDO to return database rows from your database using an associative 
    // array.  This means the array will have string indexes, where the string value 
    // represents the name of the column in your database. 
    $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); 
    ?>