What cloud tiers and tiering policies are

Cloud tiers provide storage for infrequently accessed data. You can attach an all-flash (all-SSD) aggregate to a cloud tier to store infrequently used data. You can use tiering policies to decide whether data should be moved to a cloud tier.

You can set one of the following tiering policies on a volume:

Moves the Snapshot copies of only those volumes that are currently not being referenced by the active file system. Snapshot-only policy is the default tiering policy.
Prevents the data on the volume from being moved to a cloud tier.
Moves the newly transferred data of a data protection (DP) volume to the cloud tier.
Moves the inactive (cold) data and the Snapshot copies from the active file system to the cloud tier.