How can I merge two JIRA Cloud instances?

[Joe Murray]

I have a project in one JIRA Cloud instance that I would like to move a different JIRA Cloud instance that we use. The latter has several dozen projects in it that I want to keep as is, and just add the data from the one project from the other instance. The documentation for using Import indicates that that procedure will overwrite EVERYTHING in the JIRA instance into which the data is being imported. How can I work around this limitation?

Is there a way to import from a different, non-JIRA data source that is non-destructive of existing data in the JIRA instance? If so, are there tools or documentation on how to convert the JIRA export format into the appropriate other format (eg import from JIRA into some other system then export from that system)?

Is there a way to export from both instances and merge the two JIRA export files somehow before importing the merged file? 

Can I setup an integration from one instance to the other to suck in its data?

Oh, and if this weren't enough bother, I also have the related Confluence project to move in the same manner.

[Phill Fox]

You will be pleased to know there is a straight forward process that is documented at https://confluence.atlassian.com/adminjiraserver070/restoring-a-project-from-backup-749383456.html for how to import a project from a backup. So in big picture terms backup JIRA instance A and then import from the backup into JIRA instance B.

For Confluence spaces just export the space and import it in to the second instance.

[Sylvain Brosset]

The process you mention @Phill Fox [Adaptavist] is for Server not for Cloud... I guess

[Phill Fox]

For JIRA Cloud you can export the project to move as a CSV from the tools menu and then using the CSV import tool reload the content back after you have initially created the project to which you want to restore.

[Sylvain Brosset]

Thanks, I'm gone try this technic