If you want to compress multiple segments at once, make multiple segments read-only, or move multiple segments to a different storage classification, you must create a segment set. After you create a segment set, you can run a standalone job on the entire segment set. When you run a job on a segment set, the ILM Engine runs the job on only the segments in the set.

You can add a segment to multiple segment sets. If you want to run another job on a segment set, you can edit a segment set to include new segments or remove segments.