Large size files cannot be uploaded

[Astro-CQM]

💡 Summary

Can't upload large size files smaller than file size limit set in role policy. (e.g. emoji dump from other server)

🥰 Expected Behavior

File should be uploaded (not using cloudflare)

🤬 Actual Behavior

File is not uploading with file size limit alert

📝 Steps to Reproduce

No response

💻 Frontend Environment

* Model and OS of the device(s): iPhone 17 Pro (iOS 26.5 Beta)
* Browser: Safari
* Server URL: astro.win
* Misskey: 2026.4.0-alpha.6

🛰 Backend Environment (for server admin)

* Installation Method or Hosting Service: systemd
* Misskey: 2026.4.0-alpha.6
* Node: 22.22.2
* PostgreSQL: 18.0
* Redis: 8.6.2
* OS and Architecture: Ubuntu 24.04 LTS

Do you want to address this bug yourself?

• Yes, I will patch the bug myself and send a pull request

[dosubot[bot]]

Hi @Astro-CQM! I'm Dosu and I’m helping the misskey team.

This is likely caused by Misskey's two-tier file size limit system. The effective upload limit is the minimum of two values:

1. instance.maxFileSize — a global instance-wide limit set in .config/*.yml (default: ~250 MB) [1] [2]
2. $i.policies.maxFileSizeMb — a per-user role policy limit (default: 30 MB) [3]

The frontend checks both before uploading [4]:

if ((file.size > instance.maxFileSize) || (file.size > ($i.policies.maxFileSizeMb * 1024 * 1024))) {

However, the upload dialog only displays the role policy limit to the user [5], so if your instance.maxFileSize in the YAML config is lower than what the role policy allows, you'll get rejected with no clear explanation of why.

To fix for your instance: Check your .config/default.yml for a maxFileSize setting and ensure it's equal to or greater than the role policy's maxFileSizeMb value (converted to bytes). If you haven't explicitly set maxFileSize in config, the default is ~250 MB — so if your role policy allows more than that, the instance limit will silently cap uploads.

Also note that driveCapacityMb (total storage) and maxFileSizeMb (per-file limit) are separate role policy fields [6] — make sure you've configured maxFileSizeMb specifically if you want to allow larger individual files.

There's also a 1-hour cache on instance metadata [7], so if you recently changed the config, you may need to wait or restart for changes to propagate to clients.

To reply, just mention @dosu.

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Docs are dead. Just use Dosu.

[kakkokari-gtyih]

@Astro-CQM Did you try these solutions offered by Dosu? please inform us, and if it's resolve, close the issue

• Edit your config file to increase maxFileSize (you need to restart misskey after updating config)
• Review current role policy settings (once again)
• If you are using Cloudflare, the max upload file is capped to 100MB if you are using their free tier

[Astro-CQM]

Resolved by changing value in .config/default.yml.

But this is somehow weird that role policy can be set beyond the instance configuration. since the default value in .config/example.yml was initially commented out, I assumed this meant there were no instance-level restrictions. maybe example config file should be updated or limit role policy so it doesn't set at all. it's likely that others will be confused as well.

Anyway, thanks for helping!

[syuilo]

nginxの制限の可能性もありそう

[Astro-CQM]

Likely this is not the reason due to we are using HAProxy.