[[Cache management]] in [[JMeter]] is handled by the [[JMeter/HTTP Cache Manager]]. It is a config element that checks response headers and caches or re-fetches content depending on the directives. The default size of the [[JMeter/HTTP Cache Manager]] is 5000 items, but the value is customizable. The Cache Manager changes the response codes JMeter returns depending on the headers of the items. - GET request to an app server for a resource that has not been modified: [[HTTP 304 Not Modified]] - GET request for a resource that JMeter can serve directly from cache: [[HTTP 204 No Content]] - JMeter does not actually send the request to the server in this case, since it knows that the resource should be served from the cache. - Examples > If a no-cache directive is set, JMeter will keep this in cache, but set the expires date to null which will trigger a revalidation for each request. You will generally see a HTTP response code 304 for this type of conditional request. ([View Highlight](https://instapaper.com/read/1378461920/15251796)) > no-store - If sent in a response, a cache MUST NOT store any part of either this response or the request that elicited it. ([View Highlight](https://instapaper.com/read/1378461920/15251799))" > if the "Use Cache-Control/Expires header" option is selected in the Cache Manager, JMeter will issue a HTTP response code 204 for content in its cache, otherwise it will make a conditional request and you will see a HTTP response code 304 where appropriate. ([View Highlight](https://instapaper.com/read/1378461920/15251803))"