* (Doc+) Expand watermark resolution
Relaunch https://github.com/elastic/elasticsearch/pull/116892 since the original one seems to be outdated and hard to update branch.
* Apply suggestions from code review
Co-authored-by: shainaraskas <58563081+shainaraskas@users.noreply.github.com>
---------
Co-authored-by: shainaraskas <58563081+shainaraskas@users.noreply.github.com>
Introduce max headroom settings for the low, high, and flood disk watermark stages, similar to the existing max headroom setting for the flood stage of the frozen tier. Introduce new max headrooms in HealthMetadata and in ReactiveStorageDeciderService. Add multiple tests in DiskThresholdDeciderUnitTests, DiskThresholdDeciderTests and DiskThresholdMonitorTests. Moreover, addition & subtraction for ByteSizeValue, and min.