check system $HOST
  if memory      > 75% for 5 cycles then alert
  if swap        > 25% for 5 cycles then alert
  if cpu()       > 90% for 5 cycles then alert
  if cpu(user)   > 70% for 5 cycles then alert
  if cpu(system) > 30% for 5 cycles then alert
  if cpu(wait)   > 20% for 5 cycles then alert

check filesystem rootfs with path /
  if space usage > 90% then alert
  if inode usage > 90% then alert
