Attachments only importer fails with certain ZIP file size

Summary

Attachments only importer in Atlassian Jira Cloud fails with certain ZIP file size. The failure is more consistent with files at 2GB or more in size.

No error thrown in Jira and the import just fails silently.

Current Result

Import fails without any indication.

Expected Result

1. The importer should be able to handle any size of attachments import or specify the limit.
2. If it fails, an error should be thrown.

Workaround

Split the attachments into smaller chunks e.g. project by project.

In the case where a single project contain more than 1GB total attachments size, the files can still be split on issues hierarchy level.

Make sure the hierarchy of the end ZIP file is correct. Below is an example of the hierarchy:

attachments-1.zip
└─── data
       ├── attachments
       │       ├── ProjectKey1
       │       │          └── 10000
       │       │                ├── IssueKey-1
       │       │                ├── IssueKey-2
       │       │                └── IssueKey-3
       │       ├── ProjectKey2
       │       └── ProjectKey3
       └── avatars
attachments-2.zip
└─── data
       └── attachments
               ├── ProjectKey4
               ├── ProjectKey5
               └── ProjectKey6
attachments-3.zip
└─── data
       └── attachments
               └── ProjectKey7