anchor.diff:  == Store
   
   The store module allows you to control how index data is stored and accessed on disk.
  +
  +NOTE: This is a low-level setting. Some store implementations have poor
  +concurrency or disable optimizations for heap memory usage. We recommend
  +sticking to the defaults.
   
   [float]
   [[file-system]]
  
positive.code: The Simple FS type is a straightforward implementation of file system
  storage (maps to Lucene `SimpleFsDirectory`) using a random access file.
  This implementation has poor concurrent performance (multiple threads
  will bottleneck). It is usually better to use the `niofs` when you need
  index persistence.
  
  [[niofs]]`niofs`::
  
  The NIO FS type stores the shard index on the file system (maps to
  Lucene `NIOFSDirectory`) using NIO. It allows multiple threads to read
  from the same file concurrently. It is not recommended on Windows
  because of a bug in the SUN Java implementation.
  
  [[mmapfs]]`mmapfs`::
  
  
negative.code: Elasticsearch will pick the best implementation based on the operating
  environment.
  
  The storage type can also be explicitly set for all indices by configuring the
  store type in the `config/elasticsearch.yml` file:
  
  [source,yaml]
  ---------------------------------
  index.store.type: hybridfs
  ---------------------------------
  
  It is a _static_ setting that can be set on a per-index basis at index
  