MySQL full / incremental backup script using innobackupex

backup.php

<?php
/* 
 * Backup script to create full and incremental backups using innobackupex
 * 
 * Creates a full backup once a day and periodically incremental backups using innobackupex by Percona
 * 
 * Install: create backup folder, change mysql username/password and add a crontab calling "php -f /PATH_TO_SCRIPT/backup.php" every hour
 * 
 * ---
 * Warning:
 * Incremental backups only affect XtraDB or InnoDB-based tables.
 * Other tables with a different storage engine, e.g. MyISAM, will be copied entirely each time an incremental backup is performed.
 * ---
 * 
 * innobackupex: http://www.percona.com/doc/percona-xtrabackup/2.1/innobackupex/innobackupex_script.html
 * 
 * @author Tobias Kempkensteffen <tobias.kempkensteffen@gmail.com>
 */

//MySQL user for backups
$username = "backup";
$password = "123456";

//folder to store backups
$backupFolder = "/var/mysql_backups/backups";

//number of backups (days) to keep (including today's backup)
$numberOfBackups = 7;

//period in hours to create incremental backups
$diffBackupPeriod = 3;

//backup script path
$backupScript = "/usr/bin/innobackupex";


//////////////////////////////////////////////////////////////////////////////////

//remove trailing slash
if (substr($backupFolder, -1) == "/") {
        $backupFolder = substr($backupFolder, 0, -1);
}

$backupFolderToday = $backupFolder."/".date("Y-m-d");

//check if todayi's backup folder exists
if (!file_exists($backupFolderToday)) {
        mkdir($backupFolderToday);
}

if (file_exists($backupFolderToday."/full")) {

        //create diff backup
        if ((date("G")%$diffBackupPeriod) == 0 AND date("G") > 0) {

                $currentBackupFolder = $backupFolderToday."/".date("H");

                if (file_exists($currentBackupFolder)) die("The current backup already exists\n"); //stop if backup already exists
				
				//get folder of last incremental backup (or of the full backup if no incremental backup exists)
				$lastBackup = "full";
				foreach (scandir($backupFolderToday) as $file) {

				        if (substr($file, 0, 1) == ".") continue;
				        if (!is_dir($file)) continue;
				        if (((int) $file) != $file) continue;
				        if ($file == "full") continue;

				        $lastBackup = $file;

				}
                $lastBackupFolder = $backupFolderToday."/".$lastBackup;

                echo "Create incremental backup (".$currentBackupFolder.") based on ".$lastBackupFolder."\n";
                system($backupScript." --user=".$username." --password=".$password." --incremental ".$currentBackupFolder."/ --incremental-basedir=".$lastBackupFolder." --no-timestamp");

        }

} else {

        //create full backup
        $currentBackupFolder = $backupFolderToday."/full";

        echo "Create full backup (".$currentBackupFolder.")\n";
        system($backupScript." --user=".$username." --password=".$password." ".$currentBackupFolder."/ --no-timestamp");

}





//remove old backups
$todayTS = mktime(0,0,0);
$lastValidTS = $todayTS-($numberOfBackups*(60*60*24));

foreach (scandir($backupFolder) as $folder) {

        //skip hidden files and folders
        if (substr($folder, 0, 1) == ".") continue;

        //get timestamp for backup from folder name
        $folderTS = strtotime($folder);

        //skip files and folders with invalid timestamps
        if ($folderTS == 0) continue;

        //skip up-to-date backups
        if ($folderTS > $lastValidTS) continue;

        //delete old backup
        echo 'Delete old backup '.$folder."\n";
        system("rm -R ".$backupFolder."/".$folder);

}