Best way to migrate projects and issues, history, etc from one Jira instance to another

[mc]

I'm looking for the best way to migrate multiple projects and the issues, history, comments, etc for each project to another instance of JIRA. The instance I'm migrating from is very messy. The majority of projects contain custom workflows, fields, and plugins, so the configuration needing to be in place to import with project importer would be a huge pain. I'm hoping what might work is the method of taking an entire JIRA backup of the instance we need to migrate, restore the instance, delete the projects that do not need to be migrated, take a backup, and then import that backup into the existing JIRA instance that we need to migrate the projects into. If I understand this method correctly, this should bring across the projects, project configuration, tickets, comments, and basically all of the history for the projects we're migrating. 

Now, my big question is... is this method even possible when importing into an existing JIRA instance? The documentation I read recommends this method if you are importing into a new empty instance. We're not importing into a new empty instance, we need to import the projects + all history from Instance A into a pre-existing instace of JIRA B, without losing anything from pre-existing JIRA instance B. What is the best way to do this?

[Jobin Kuruvilla [Adaptavist] · Accepted solution]

You cannot import the backup as a whole into an existing JIRA because that will overwrite what you have in target JIRA.

You can only do project imports but that means that you will have to manually or programmatically create the required configurations in the target project. Also, the JIRA instances should be on the same version.

[mc]

And how can I migrate the issues? From what I understand, you cannot take a full backup of the issues and import them into the project on the new instance without losing some data. Any ideas for that?

[Jobin Kuruvilla [Adaptavist]]

When you import projects, issues and all its history comes as part of that. See https://confluence.atlassian.com/display/JIRA/Restoring+a+Project+from+Backup

[Sachin Dhamale]

hi Jobin,

Is it possible programmatically to merge one JIRA instance with another with all configuration. or any other way to do this. 

[Lillian Shibata-Salley]

I did an import with few errors - can I fix the errors and just to a re-import to overwrite the initial import data? Will the import be based on the key/ID? (Don't want to duplicate records).

Thanks,

[MattS]

This is a merge of data. I believe there is work planned for data center around this but right now it is hard to do and also preserve all add-on data. Atlassian Experts can help with this work but it takes a fair bit of effort.