title: Understanding buffers/cache in linux `free -m`
body: <p>Just looking for some quick help regarding <code>free -m</code> output on Linux. Here's an example on one of my servers:</p>
  
  <pre><code>  $free -m
                 total       used       free     shared    buffers     cached
    Mem:         14881      14813         68          0        262        883
    -/+ buffers/cache:      13667       1213
    Swap:         4095        240       3855
  </code></pre>
  
  <p>I understand the kernel can and will use available memory for disk caching to speed up the system.</p>
  
  <p>Normally, I look at the second value in the "free" column, in the above case it's 1213. It's normally a lot higher than this. </p>
  
  <p>I guess I am looking to understand what the two outputs next to '-/+ buffers/cache' mean. From what I can see, the system truly is low on memory (only 1213MB available for applications to use) and the OS actually <em>needs</em> 13GB for caching?</p>