Espero que os sirva de ayuda este script en php que me he encontrado en un foro privado para realizar respaldos programados en Plesk, aqui se los copypasteo:
<?php
$maintain = 3; // Cuantos respaldos conservar
$prefix = «plesk»;
$path = «/mnt/backup/»; //dont delete slashset_time_limit(0);
$day = date(«d»);
$month = date(«m»);
$year = date(«y»);$backupfile = «$prefix$day$month$year»;
$comando = «/usr/local/psa/bin/pleskbackup all $path$backupfile»;
@exec($comando);$unixtime = mktime(0,0,0,$month, $day, $year); // present time
$todelete = $unixtime – ($maintain *= 86400);// create file name to delete
$day_d = date(«d», $todelete);
$month_d = date(«m», $todelete);
$year_d = date(«y», $todelete);$backupdel = «$prefix$day_d$month_d$year_d»;
if (@file_exists(«$path$backupdel»)) {
@exec(«rm -f $path$backupdel»); // Delete file
}?>