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When you deploy a system snapshot in "merge" mode, all the configuration in the snapshot is "merged" with the existing Jira configuration. This means that all objects from the snapshot which that are not present in the system will be added, and the configuration of all objects which that are present in both the snapshot and the target Jira instance will be replaced with the one from the snapshot.
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Project "Library" is present in the snapshot but not in the target Jira instance - A new project, "Library", will be created(added) and will have the same configuration as in the snapshot.
Project "Marketing" is present in the snapshot, and the target Jira instance - The configuration of the "Marketing" project will be replaced with the one from the snapshot.
Project "Human Resources" is not present in the snapshot but exists in the target Jira instance - The project "Human Resources" will be deleted.
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Restore mode is suitable for the case when you want to create a "staging" Jira instance, which is an exact copy of the "production" Jira instance (a.k.a refresh staging from production). Using Configuration Manager to achieve that is much faster than restoring an XML backup of the "production" system to the "staging" system. Sometimes, using Configuration Manager is the only possible way to transfer configurations and issues, especially when you're working with large Jira instances, where creating a backup leads to performance degradation of the production system and the backup is so large that you're not able to transfer it and restore it to the "staging" systemdue to its size. Using Configuration Manager will allow you to perform such a "refresh" in just a few minutes compared to hours for really large Jira instances.
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