With this commit we add the `.cfs` file extension to the list of file
types that are memory-mapped by hybridfs. `.cfs` files combine all files
of a Lucene segment into a single file in order to save file handles. As
this strategy is only used for "small" segments (less than 10% of the
shard size), it is benefical to memory-map them instead of accessing
them via NIO.

Relates elastic#36668

With this commit we add the `.cfs` file extension to the list of file
types that are memory-mapped by hybridfs. `.cfs` files combine all files
of a Lucene segment into a single file in order to save file handles. As
this strategy is only used for "small" segments (less than 10% of the
shard size), it is benefical to memory-map them instead of accessing
them via NIO.

Relates elastic#36668

With this commit we add the `.cfs` file extension to the list of file
types that are memory-mapped by hybridfs. `.cfs` files combine all files
of a Lucene segment into a single file in order to save file handles. As
this strategy is only used for "small" segments (less than 10% of the
shard size), it is benefical to memory-map them instead of accessing
them via NIO.

Relates #36668

With this commit we add the `.cfs` file extension to the list of file
types that are memory-mapped by hybridfs. `.cfs` files combine all files
of a Lucene segment into a single file in order to save file handles. As
this strategy is only used for "small" segments (less than 10% of the
shard size), it is benefical to memory-map them instead of accessing
them via NIO.

Relates #36668

* elastic/master:
  Avoid double term construction in DfsPhase (elastic#38716)
  Fix typo in DateRange docs (yyy → yyyy) (elastic#38883)
  Introduced class reuses follow parameter code between ShardFollowTasks (elastic#38910)
  Ensure random timestamps are within search boundary (elastic#38753)
  [CI] Muting  method testFollowIndex in IndexFollowingIT
  Update Lucene snapshot repo for 7.0.0-beta1 (elastic#38946)
  SQL: Doc on syntax (identifiers in particular) (elastic#38662)
  Upgrade to Gradle 5.2.1 (elastic#38880)
  Tie break search shard iterator comparisons on cluster alias (elastic#38853)
  Also mmap cfs files for hybridfs (elastic#38940)
  Build: Fix issue with test status logging (elastic#38799)
  Adapt FullClusterRestartIT on master (elastic#38856)
  Fix testAutoFollowing test to use createLeaderIndex() helper method.
  Migrate muted auto follow rolling upgrade test and unmute this test (elastic#38900)
  ShardBulkAction ignore primary response on primary (elastic#38901)
  Recover peers from translog, ignoring soft deletes (elastic#38904)
  Fix NPE on Stale Index in IndicesService (elastic#38891)
  Smarter CCR concurrent file chunk fetching (elastic#38841)
  Fix intermittent failure in ApiKeyIntegTests (elastic#38627)
  re-enable SmokeTestWatcherWithSecurityIT (elastic#38814)

With this commit we add the `.cfs` file extension to the list of file
types that are memory-mapped by hybridfs. `.cfs` files combine all files
of a Lucene segment into a single file in order to save file handles. As
this strategy is only used for "small" segments (less than 10% of the
shard size), it is benefical to memory-map them instead of accessing
them via NIO.

Relates #36668

Backport of elastic/elasticsearch#38940

Backport of elastic/elasticsearch#38940

Backport of elastic/elasticsearch#38940