anchor.diff:  === Lucene Loses Data On File Descriptors Failure (STATUS: DONE, v0.90.0)
   
   When a process runs out of file descriptors, Lucene can causes an index to be completely deleted. This issue was fixed in Lucene ({JIRA}4870[version 4.2.1]) and fixed in an early version of Elasticsearch. See issue {GIT}2812[#2812].
  -
  
positive.code: nodes have sent their joins request (based on the `minimum_master_nodes` settings) the cluster state is updated.
  {GIT}12161[#12161]
  
  
  [float]
  === Write index metadata on data nodes where shards allocated (STATUS: ONGOING)
  
  Today, index metadata is written only on nodes that are master-eligible, not on
  data-only nodes.  This is not a problem when running with multiple master nodes,
  as recommended, as the loss of all but one master node is still recoverable.
  However, users running with a single master node are at risk of losing
  their index metadata if the master fails.  Instead, this metadata should
  also be written on any node where a shard is allocated. {GIT}8823[#8823]
  
  [float]
  === Better file distribution with multiple data paths (STATUS: ONGOING)
  
  Today, a node configured with multiple data paths distributes writes across
  all paths by writing one file to each path in turn.  This can mean that the
  failure of a single disk corrupts many shards at once.  Instead, by allocating
  an entire shard to a single data path, the extent of the damage can be limited
  to just the shards on that disk. {GIT}9498[#9498]
  
  [float]
  === OOM resiliency (STATUS: ONGOING)
  
  The family of circuit breakers has greatly reduced the occurrence of OOM
  exceptions, but it is still possible to cause a node to run out of heap
  space.  The following issues have been identified:
  
  * Set a hard limit on `from`/`size` parameters {GIT}9311[#9311]. (STATUS: ONGOING)
  * Prevent combinatorial explosion in aggregations from causing OOM {GIT}8081[#8081]. (STATUS: ONGOING)
  * Add the byte size of each hit to the request circuit breaker {GIT}9310[#9310]. (STATUS: ONGOING)
  
  [float]
  === Mapping changes should be applied synchronously (STATUS: ONGOING)
  
  When introducing new fields using dynamic mapping, it is possible that the same
  field can be added to different shards with different data types.  Each shard
  
negative.code: We are committed to tracking down and fixing all the issues that are posted.
  
  [float]
  === Use two phase commit for Cluster State publishing (STATUS: ONGOING, v3.0.0)
  
  A master node in Elasticsearch continuously https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery-zen.html#fault-detection[monitors the cluster nodes]
  and removes any node from the cluster that doesn't respond to its pings in a timely
  