An index’s lifecycle policy specifies which phases are applicable, what actions are performed in each phase, and when it transitions between phases.
Hot: The index is actively being updated and queried.
96:1 GB of Disk to RAM ratio, requires 2x storage to provide redundancy
Warm: The index is no longer updated but is still queried.
200:1 GB of Disk to RAM ratio, requires 2x storage to provide redundancy
Cold: The index is no longer updated and is queried infrequently. The information still needs to be searchable, but it’s okay if those queries are slower.
96:1 GB of Disk to RAM ratio, if straight from hot to cold, 200:1 ratio if warm also used. 1x storage, redundancy provided by snapshot
Frozen: The index is no longer updated and is queried rarely. The information still needs to be searchable, but it’s okay if those queries are extremely slow.
Purely searchable snapshot, only metadata mounted in the cluster.
Delete: The index is no longer needed and can safely be removed.
For more information, see Index Lifecycles and LM Overview from Elasticsearch Documentation.