librenms-librenms/includes/polling/hr-mib_storage.inc.php

<?php

/// HOST-RESOURCES-MIB - Storage Objects

$dq = mysql_query("SELECT * FROM storage WHERE host_id = '" . $device['device_id'] . "'");
while ($dr = mysql_fetch_array($dq)) {
  $hrStorageIndex = $dr['hrStorageIndex'];
  $hrStorageAllocationUnits = $dr['hrStorageAllocationUnits'];
  $hrStorageSize = $dr['hrStorageAllocationUnits'] * $dr['hrStorageSize']; 
  $hrStorageDescr = $dr['hrStorageDescr'];
  $cmd  = $config['snmpget'] . " -m HOST-RESOURCES-MIB -O qv -" . $device['snmpver'] . " -c " . $device['community'] . " " . $device['hostname'].":".$device['port'] . " hrStorageUsed.$hrStorageIndex";
  $used_units = trim(shell_exec($cmd));
  $used = $used_units * $hrStorageAllocationUnits;
  $perc = round($used / $hrStorageSize * 100, 2);
  $filedesc = str_replace("\"", "", str_replace("/", "_", $hrStorageDescr));
  $old_storage_rrd = $config['rrd_dir'] . "/" . $device['hostname'] . "/storage-" . $filedesc . ".rrd";
  $storage_rrd  = $config['rrd_dir'] . "/" . $device['hostname'] . "/hrStorage-" . $hrStorageIndex . ".rrd";
  if(is_file($old_storage_rrd)) { shell_exec("mv $old_storage_rrd $storage_rrd"); }
  if (!is_file($storage_rrd)) {
    shell_exec($config['rrdtool'] . " create $storage_rrd \
     --step 300 \
     DS:size:GAUGE:600:0:U \
     DS:used:GAUGE:600:0:U \
     DS:perc:GAUGE:600:0:U \
     RRA:AVERAGE:0.5:1:800 \
     RRA:AVERAGE:0.5:6:800 \
     RRA:AVERAGE:0.5:24:800 \
     RRA:AVERAGE:0.5:288:800 \
     RRA:MAX:0.5:1:800 \
     RRA:MAX:0.5:6:800 \
     RRA:MAX:0.5:24:800 \
     RRA:MAX:0.5:288:800");
  }  
  rrdtool_update($storage_rrd, "N:$hrStorageSize:$used:$perc");
  mysql_query("UPDATE `storage` SET `hrStorageUsed` = '$used_units', `storage_perc` = '$perc' WHERE storage_id = '" . $dr['storage_id'] . "'");
    if($dr['storage_perc'] < '40' && $perc >= '40') {
    if($device['sysContact']) { $email = $device['sysContact']; } else { $email = $config['email_default']; }
    $msg  = "Disk Alarm: " . $device['hostname'] . " " . $dr['hrStorageDescr'] . " is " . $perc;
    $msg .= "% at " . date('l dS F Y h:i:s A');
    mail($email, "Disk Alarm: " . $device['hostname'] . " " . $dr['hrStorageDescr'], $msg, $config['email_headers']);
    echo("Alerting for " . $device['hostname'] . " " . $dr['hrStorageDescr'] . "\n");
  }
}