reuse segments

Sorry this may sound silly, just wanted to know if we can copy the segments created in local storage to S3 and then set up S3 as deep storage.
Has anyone tried this?

Yes, theoretically, It is possible to do.
However you will have to manually update the segment metadata entries in the database as there is no tools available to update metadata of segments from S3.

There is a PR out there that attempts to discover segments from S3 and update metadata - https://github.com/druid-io/druid/pull/3446

Thanks Nishant.Currently I am using derby metadata store and looks like there is no provision to modify the metadata entry.I will be setting up a PostgreSQL store.