NAME

       cache.config  -  the cache.config file (by default, located in /usr/local/etc/trafficserver/) defines how
       Traffic Server caches web objects. You can add caching rules to specify the following:

          • Not to cache objects from specific IP addresses

          • How long to pin particular objects in the cache

          • How long to consider cached objects as fresh

          • Whether to ignore no-cache directives from the server

       IMPORTANT:
          After you modify the cache.config file, navigate to the Traffic Server bin  directory;  then  run  the
          traffic_line  -x  command to apply changes. When you apply the changes to a node in a cluster, Traffic
          Server automatically applies the changes to all other nodes in the cluster.

FORMAT

       Each  line  in  the  cache.config  file  contains  a  caching  rule.  Traffic  Server  recognizes   three
       space-delimited tags:

          primary_destination=value secondary_specifier=value action=value

       You  can  use  more  than  one  secondary  specifier  in  a  rule. However, you cannot repeat a secondary
       specifier. The following list shows the possible primary destinations with allowed values.

       dest_domain
              A requested domain name. Traffic Server matches the domain name of the destination from the URL in
              the request.

       dest_host
              A requested hostname. Traffic Server matches the hostname of the destination from the URL  in  the
              request.

       dest_ip
              A requested IP address. Traffic Server matches the IP address of the destination in the request.

       url_regex
              A regular expression (regex) to be found in a URL.

       The  secondary  specifiers  are  optional  in  the  cache.config  file. The following list shows possible
       secondary specifiers with allowed values.

       port   A requested URL port.

       scheme A request URL protocol: http or https.

       prefix A prefix in the path part of a URL.

       suffix A file suffix in the URL.

       method A request URL method: get, put, post, trace.

       time   A time range, such as 08:00-14:00.

       src_ip A client IP address.

       The following list shows possible actions and their allowed values.

       action One of the following values:

              • never-cache configures Traffic Server to never cache specified objects.

              • ignore-no-cache configures Traffic Server to ignore all Cache-Control: no-cache headers.

              • ignore-client-no-cache configures Traffic Server to ignore Cache-Control: no-cache headers  from
                client requests.

              • ignore-server-no-cache  configures Traffic Server to ignore Cache-Control: no-cache headers from
                origin server responses.

              • cluster-cache-local configures the cluster cache to allow for this content to be stored  locally
                on every cluster node.

       cache-responses-to-cookies
              Change  the  style of caching with regard to cookies. This effectively overrides the configuration
              parameter proxy.config.http.cache.cache_responses_to_cookies and uses the  same  values  with  the
              same semantics. The override happens only for requests that match.

       pin-in-cache
              Preserves  objects in cache, preventing them from being overwritten.  Does not affect objects that
              are determined not to be cacheable. This setting can have performance issues, and  severely affect
              the cache.  For instance, if the primary destination matches all objects, once the cache is  full,
              no  new  objects  could  get written as nothing would be evicted.  Similarly, for each cache-miss,
              each object would incur extra checks to  determine  if  the  object  it  would  replace  could  be
              overwritten.

              The  value  is  the amount of time you want to keep the object(s) in the cache. The following time
              formats are allowed:

              • d for days; for example: 2d

              • h for hours; for example: 10h

              • m for minutes; for example: 5m

              • s for seconds; for example: 20s

              • mixed units; for example: 1h15m20s

       revalidate
              For objects that are in cache, overrides the the amount of time the object(s) are to be considered
              fresh. Use the same time formats as pin-in-cache.

       ttl-in-cache
              Forces object(s) to become cached, as if they had a Cache-Control: max-age:<time> header.  Can  be
              overruled  by  requests  with cookies. The value is the amount of time object(s) are to be kept in
              the cache, regardless of Cache-Control response headers. Use the same time formats as pin-in-cache
              and revalidate.

EXAMPLES

       The following example configures Traffic Server  to  revalidate  gif  and  jpeg  objects  in  the  domain
       mydomain.com  every  6  hours, and all other objects in mydomain.com every hour. The rules are applied in
       the order listed.

          dest_domain=mydomain.com suffix=gif revalidate=6h
          dest_domain=mydomain.com suffix=jpeg revalidate=6h
          dest_domain=mydomain.com revalidate=1h

       Force a specific regex to be in cache between 7-11pm of the server's time for 26hours.

          url_regex=example.com/articles/popular.* time=19:00-23:00 ttl-in-cache=1d2h

       Prevent objects from being evicted from cache:
          url_regex=example.com/game/.* pin-in-cache=1h

COPYRIGHT

       2014, dev@trafficserver.apache.org

5.3                                              April 18, 2016                                  CACHE.CONFIG(5)