You can use the index-level
_tier_preference setting to control
which data tier an index is allocated to.
This setting corresponds to the data node roles:
Data tier allocation settingsedit
Assign the index to the first tier in the list that has an available node.
This prevents indices from remaining unallocated if no nodes are available
in the preferred tier.
For example, if you set
data_warm,data_hot, the index is allocated to the warm tier if there are nodes with the
data_warmrole. If there are no nodes in the warm tier, but there are nodes with the
data_hotrole, the index is allocated to the hot tier. Used in conjunction with data tiers.