title: Redis - monitoring memory usage
body: <p>I am currently testing insertion of keys in a database Redis (on local).
  I have more than 5 millions keys and I have just 4GB RAM so at one moment I reach capacity of RAM and swap fill in (and my PC goes down)...</p>
  
  <p>My problematic : How can I make monitoring memory usage on the machine which has the Redis database, and in this way alert no more insert some keys in the Redis database ?</p>
  
  <p>Thanks.</p>