Index-level data tier allocation filteringedit

You can use index-level allocation settings to control which data tier the index is allocated to. The data tier allocator is a shard allocation filter that uses two built-in node attributes: _tier and _tier_preference.

These tier attributes are set using the data node roles:

The data role is not a valid data tier and cannot be used for data tier filtering. The frozen tier stores partially mounted indices exclusively.

Data tier allocation settingsedit

index.routing.allocation.include._tier_preference
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 index.routing.allocation.include._tier_preference to data_warm,data_hot, the index is allocated to the warm tier if there are nodes with the data_warm role. If there are no nodes in the warm tier, but there are nodes with the data_hot role, the index is allocated to the hot tier.