anchor.diff:  by not using a _<neverUse>_ or _<alwaysUse>_ element (which uses the
   default behavior). When you delete the data files, delete the
   corresponding indices.
  +
   2.  If you need to keep the index files separate from your data files,
   set __<alwaysUse>true</alwaysUse>__, and use
   __<policy>nestedDirectory</policy>__. There is currently no way to
  
positive.code: Write permission will be determined by what rights the _Tomcat user_ has
  (the user that starts up Tomcat). For security reasons, you want to
  carefully limit the file permissions of the Tomcat user.
  2.  The policy must be set to one of _oneDirectory_ or _nestedDirectory_
  (the default). _oneDirectory_ will put all index files into the same
  directory, while _nestedDirectory_ will preserve the directory structure
  of the index files. Use _nestedDirectory_ for large collections of
  files.
  3.  Every *scour* amount of time, any files in the cache that are older
  than *maxAge* will be removed. To turn off scouring, set the scour time
  to 0 (eg ``0 hours''), or leave out the <scour> element. Typically you
  
negative.code: change, set *scour* to ``-1'' to disable the operation. Otherwise, make
  *maxAge* longer than the longest time between changes. Basically, you
  don’t want to remove active aggregations.
  
  *cachePathPolicy* controls _how_ cache files are stored in *dir*. It must be set to one of `oneDirectory` or
  `nestedDirectory`
   (the default). `oneDirectory` will put all cache files into the same directory, while `nestedDirectory` will preserve
   their directory structure. Use `nestedDirectory` for large aggregations, as some file systems struggle when a
   directory contains thousands of files.
  
  This cache information is intended to be permanent; it stores coordinate
  information from each file in the aggregation, so that the file does not
  