It may be a rare occurence but it can happen, accidental deletion of the board even with administrator, or hackings/etc. same for accidental deletion of epics and all subsequent issues and tasks under it.
It would be good to have a backup. I was thinking copy board every two weeks when the sprints start so everything is tasked up and updated at those intervals to enable good backups but the ideal way is mirror(s) really.
We already do this on source control, have a mirror whereby if something happens to the original then the backup is up in an instant.
How do you guys all backup your Jira Project Management store?
Cheers