anchor.diff:  --------------------------------------------------
   // CONSOLE
   // TEST[setup:twitter]
  -
  -
  -NOTE: Percentage values refer to used disk space, while byte values refer to
  -free disk space. This can be confusing, since it flips the meaning of high and
  -low. For example, it makes sense to set the low watermark to 10gb and the high
  -watermark to 5gb, but not the other way around.
  -
  +--
   
   `cluster.info.update.interval`::
   
  
positive.code:   "transient": {
      "cluster.routing.allocation.disk.watermark.low": "80%",
      "cluster.routing.allocation.disk.watermark.high": "50gb",
      "cluster.info.update.interval": "1m"
    }
  }
  --------------------------------------------------
  // CONSOLE
  
  NOTE: Prior to 2.0.0, when using multiple data paths, the disk threshold
  decider only factored in the usage across all data paths (if you had two
  data paths, one with 50b out of 100b free (50% used) and another with
  40b out of 50b free (80% used) it would see the node's disk usage as 90b
  out of 150b). In 2.0.0, the minimum and maximum disk usages are tracked
  separately.
  
negative.code:     the node.
  
  `cluster.routing.allocation.disk.watermark.floodstage`::
  +
  --
      Controls the floodstage 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 floodstage.
      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.
  