Trace retention is an age-based policy for a client. It is not a per-span attribute filter.

How retention works

A client retention policy defines how many days accepted spans remain available. Supported periods are 7, 15, or 30 days, with a configured default of 15 days; confirm the available values and active policy with the administrator because they can differ by release or client.
Changing the policy affects data after ingestion. It does not restore traces already dropped by sampling, and it does not selectively retain spans based on attributes. Treat expired data as unavailable after expiry cleanup.

Configure carefully

Before changing a policy, confirm the client, accepted value, approval path, and required permission with the OpsRamp administrator. Viewing a policy requires TRACE_VIEW, creating one requires ADMINISTRATION, and deleting one requires TRACE_MANAGE. The management workflow available to an operator can vary by deployment.
If a requirement is to exclude particular telemetry before storage, design that at the collection or sampling stage with the platform owner. Do not describe that behavior as a retention filter; dropping data before ingestion is different from expiring stored data by age.