anchor.diff:  [[disk-allocator]]
   === Disk-based Shard Allocation
   
  -Elasticsearch factors in the available disk space on a node before deciding
  -whether to allocate new shards to that node or to actively relocate shards
  -away from that node.
  +Elasticsearch considers the available disk space on a node before deciding
  +whether to allocate new shards to that node or to actively relocate shards away
  +from that node.
   
   Below are the settings that can be configured in the `elasticsearch.yml` config
   file or updated dynamically on a live cluster with the
  
positive.code: 
  `cluster.routing.allocation.disk.watermark.low`::
  
      Controls the low watermark for disk usage. It defaults to 85%, meaning ES will
      not allocate new shards to nodes once they have more than 85% disk used. It
      can also be set to an absolute byte value (like 500mb) to prevent ES from
      allocating shards if less than the configured amount of space is available.
  
  `cluster.routing.allocation.disk.watermark.high`::
  
      Controls the high watermark. It defaults to 90%, meaning ES will attempt to
      relocate shards to another node if the node disk usage rises above 90%. It can
      also be set to an absolute byte value (similar to the low watermark) to
      relocate shards once less than the configured amount of space is available on
      the node.
  
  `cluster.routing.allocation.disk.watermark.flood_stage`::
  +
  --
  Controls the flood stage watermark. It defaults to 95%, meaning ES enforces
  a read-only index block (`index.blocks.read_only_allow_delete`) on every
  index that has one or more shards allocated on the node that has at least
  one disk exceeding the flood stage.  This is a last resort to prevent nodes
  from running out of disk space.  The index block must be released manually
  once there is enough disk space available to allow indexing operations to
  continue.
  
  NOTE: You can not mix the usage of percentage values and byte values within
  these settings. Either all are set to percentage values, or all are set to byte
  
negative.code: `cluster.routing.allocation.disk.include_relocations`::
  
      Defaults to +true+, which means that Elasticsearch will take into account
      shards that are currently being relocated to the target node when computing
      a node's disk usage. Taking relocating shards' sizes into account may,
      however, mean that the disk usage for a node is incorrectly estimated on
      the high side, since the relocation could be 90% complete and a recently
      retrieved disk usage would include the total size of the relocating shard
      as well as the space already used by the running relocation.
  
  
  NOTE: Percentage values refer to used disk space, while byte values refer to
  