CACHE_STORAGE_DIRECTORY enables a local cache of segment files copied from the primary/secondary storage. It only makes sense if the local NVME is ephemeral while the primary data dir is trustworthy but slow.

CACHE_STORAGE_DIRECTORY=/humio-cache
CACHE_STORAGE_PERCENTAGE=90

This is generally not recommended as it is more efficient to use the fast local drive as your primary storage, use bucket storage for the long term stable storage, and USING_EPHEMERAL_DISKS set to true. Caching degrades performance if turned on in that case.

See CACHE_STORAGE_PERCENTAGE for more information.