Add docs for filesystem health checks (#59134)

Documents the feature and settings introduced in #52680.

Co-authored-by: James Rodewig <james.rodewig@elastic.co>
This commit is contained in:
David Turner 2020-07-07 14:14:35 +01:00
parent 664b546771
commit 8f4f844e6e
2 changed files with 26 additions and 0 deletions

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@ -245,3 +245,22 @@ WARNING: This setting replaces the `discovery.zen.no_master_block` setting in
earlier versions. The `discovery.zen.no_master_block` setting is ignored.
--
`monitor.fs.health.enabled`::
(<<cluster-update-settings,Dynamic>>, boolean) If `true`, the node runs
periodic <<cluster-fault-detection-filesystem-health,filesystem health
checks>>. Defaults to `true`.
`monitor.fs.health.refresh_interval`::
(<<time-units, Time value>>) Interval between successive
<<cluster-fault-detection-filesystem-health,filesystem health checks>>.
Defaults to `2m`.
`monitor.fs.health.slow_path_logging_threshold`::
(<<time-units, Time value>>) If a
<<cluster-fault-detection-filesystem-health,filesystem health checks>>
takes longer than this threshold then {es} logs a warning. Defaults to
`5s`.

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@ -18,3 +18,10 @@ Similarly, if a node detects that the elected master has disconnected, this
situation is treated as an immediate failure. The node bypasses the timeout and
retry settings and restarts its discovery phase to try and find or elect a new
master.
[[cluster-fault-detection-filesystem-health]]
Additionally, each node periodically verifies that its data path is healthy by
writing a small file to disk and then deleting it again. If a node discovers
its data path is unhealthy then it is removed from the cluster until the data
path recovers. You can control this behavior with the
<<modules-discovery-settings,`monitor.fs.health` settings>>.