This script takes a snap shot of volume in AWS.

aws-volume-backup.php

<?php
// Include the SDK using the Composer autoloader
require '/AWS_LIB_PATH/aws-autoloader.php';

use Aws\Common\Aws;

/// Create a service locator using a configuration file
$aws = Aws::factory(array(
    'region' => 'eu-west-1', // define zone here
    'key'    => 'API KEY', // define your api key here
    'secret' => 'API SECRET', // define your api secret here
));

$ec2Client = $aws->get('ec2');

$result = $ec2Client->createSnapshot(array(
    //'DryRun' => true || false,
    // VolumeId is required
    'VolumeId' => 'VOLUME ID', // define volume id
    'Name' => 'Auto Backup',
    'Description' => 'Backup Generated at '. date('F j, Y, H:i:s'),
));

//Save this script and in cron I added this entry to run every night
//30 2 * * * php /home/meraj/aws-volume-backup.php