Starting with version 7.10, Jira Software Data Center allows administrators to archive projects.
The archived issues become read-only and can only be accessed through a direct link. They are removed from the Lucene index and will no longer be part of search results, even if they match the search criteria.
Archived Issues in Structure
Archived issues will not be visible in Structure – even if they were added manually, and even in the archived structures.
When you archive a project, check for structures that have issues from that project. Contact the users to see if they are okay with the archived issues disappearing from the structures.
Restoring an Archived Project
When you restore a project from archive, you run a project reindex. After the reindex has finished, the issues should reappear in Structure.
Since Structure has internal caching for which issues are visible to which users, it might take a few minutes after the reindex completes for issues to reappear in Structure. To force the internal caches to clear and see the restored issues in structures immediately, use the "force reload" action from your browser (Shift+Reload).