The stories or all other planning activities, where does the data get stored?
Welcome to the Atlassian Community!
For Data Center, all the data lives in the database, apart from attachments, which live on the shared storage. The installation and working data also lives on each of the nodes in the cluster, alongside the shared storage.
Many useful information have already been given here, as soon as you had a look into database to see that all the data you asked for is stored there it might be an important step to think about the data is backed-up.
Please do not forget to refer to the article stated below:
https://confluence.atlassian.com/adminjiraserver/backing-up-data-938847673.html