Before you start please confirm the following.

• Yes, I've searched similar issues on GitHub.
• Yes, I've checked whether this issue is covered in the Portainer documentation or knowledge base.

Problem Description

Trying to download a backup using the "Back up Portainer" section in the settings does not work. An error message stating

Failure
Unable to download backup

appears in the top right corner.

Expected Behavior

When clicking the "Download backup" button I expect to receive a backup file of some kind.

Actual Behavior

Only an error message appears in the top right corner.

Steps to Reproduce

1. Open Portainer settings
2. Scroll down to the backup section, select "Download backup file" (no password) and click the download button. This causes the error to occur.

Portainer logs or screenshots

Performing these steps while looking at the network tab in the Chrome DevTools reveals a more concrete error message related to writing a tar file. No entries are written to the log of the portainer container.

{
    "message": "Failed to create backup",
    "details": "Failed to make an archive: archive/tar: write too long"
}

Portainer version

2.19.1

Portainer Edition

Business Edition (BE/EE) with Professional or Enterprise license

Platform and Version

MicroK8s 1.27.8

OS and Architecture

Ubuntu 22.04 LTS

Browser

Chrome 115.0.5790.102

What command did you use to deploy Portainer?

Installation via Helm with the following values:

enterpriseEdition:
  enabled: true
tls:
  force: true
nodeSelector:
  kubernetes.io/hostname: XYZ

Additional Information

The PersistentVolume for Portainer is provided using the official CSI-SMB Driver.