Bulk Clone a very large number of issues

It is possible to Bulk Clone up to 100,000 issues at once with Deep Clone for Jira. However, we recommend doing smaller Bulk Clones whenever possible (for example, cloning distinct projects individually).

If cloning a very large number of issues at once cannot be avoided, please consider the following:

The more issues are being cloned, the longer it takes to fetch the issues, configure the clone options and run the bulk clone process.
In the most extreme scenario i.e. 100,000 issues it will take several hours to fetch all issues and configure the clone options, and several days to actually clone them. For technical reasons, Deep Clone for Jira cannot fetch or create issues faster.
After having fetched the issues, the whole UI will be less responsive, although still usable, because of the amount of data that has to be loaded in the browser.
When changing the “Target issue type”, “Subtask issue type” or “Edit Fields”, it may take some time to refresh the page, as each and every issue needs to be verified. The refresh time will be longer if subtasks are being cloned or if issues fail the verification, e.g. because of missing required fields. The performance of your computer and whether other performance-intensive processes are running will also highly impact the refresh time.
Keep in mind that depending on your notification scheme, cloning issues might send email notifications to users. Read more about how to prevent notifications.
If you’re cloning between projects, make sure that all required issue fields are also available in the target project. Read more about migrating issues between projects.
If you want to clone the issue status, make sure that the workflow allows it. Read more about cloning the issue status.