In our production environment, we take backup of our ES daily to S3 repository. Now since the process is year long and we have a huge list of snapshot, we decided to move the old snapshots from S3 to Glacier. Following are my questions related to the process:
1.) I presume moving snapshots from S3 to Glacier is equivalent to deleting a snapshot. Am I right?
2.) As per the documentation, when a snapshot is deleted, Elasticsearch deletes all files that are associated with the deleted snapshot and not used by any other snapshots. Actually, I want to understand how this process works. Does a new snapshot only contains a delta of documents changed/deleted/created from the last snapshot? How does deletion of any snapshot has any impact on losing any data and during restore operations?
Any help would be appreciated.