title: What are the downsides of specifying synonyms directly in config instead of using synonyms_path
body: <p>I have around 440 kB of text files with Elastic Search synonyms.</p>
  
  <p>For the moment, these synonyms are simply placed on every node's disk, and I use the configuration property <code>synonyms_path</code>.</p>
  
  <p>Something like this (from the docs)</p>
  
  <pre><code>{
    "filter" : {
      "synonym" : {
        "type" : "synonym",
         "synonyms_path" : "analysis/synonym.txt"
      }
    }
  }
  </code></pre>
  
  <p>As these synonyms are regularly updated, it would be simpler to declare them directly in the filter configuration of each index (see the example)</p>
  
  <pre><code>{
    "filter" : {
      "synonym" : {
        "type" : "synonym",
         "synonyms" : [
           "i-pod, i pod =&gt; ipod",
           "universe, cosmos"
         ]
      }
    }
  }
  </code></pre>
  
  <p>But <a href="https://www.elastic.co/guide/en/elasticsearch/reference/5.0/analysis-synonym-tokenfilter.html" rel="nofollow noreferrer">the documentation</a> seems to discourage of doing like this:</p>
  
  <blockquote>
    <p>However, it is recommended to define large synonyms set in a file using synonyms_path, because specifying them inline increases cluster size unnecessarily.</p>
  </blockquote>
  
  <p>So I have two questions:</p>
  
  <ol>
  <li>How large is large, when specifying synonyms directly in the configuration?</li>
  <li>What are the downsides of doing like this with <em>large</em> definitions. Specifically, what does it mean to increase the <strong>cluster size</strong>?</li>
  </ol>