Host images attachments on CDN or not?

[JOGARA]

I have been playing with the S3 file adapter and it is working just fine.
But the documentation only suggests servicing the "avatar images and attachment thumbnails" and JS via the CDN public link.
Image attachments, which make up most of the data (not requests as avatars and thumbs see more requests), are to be served via the forum's host.

We now need to add support for the internal_data directory stuff too. Generally, this is attachments and any other stuff that should be "private". Back to config.php and the code to add is very similar:

Using DigitalOcean Spaces or Amazon S3 for file storage in XF 2.1 & XF 2.2

XenForo Version Compatibility The download is only compatible with XenForo 2.1 and XenForo 2.2. XenForo 2.3 is supported by following the guide but the download attached to this resource is no longer required. Why this guide? Since XenForo...

xenforo.com

Is this just for permission's sake? Like having to have a user logged in to view the larger attachment.
I presume files uploaded to private messages and private forums are also stored in both data storage sets, but thumbs are accessible publically anyway so they are not actually truly private.

If my forum has no user registered requirement to view the actual attachment, then is it okay to serve everything via the CDN rather than one but not the other?
Am I missing anything here?

 

[briansol]

Yes, attachments have permissions on them as you mention for private forums/etc, so it streams through the server. You can still store the file on s3 and stream it through to the end user.

The caching advantages are a bit lost but the storage is still a win.

Bypassing the stream and serving direct from the CDN is something that the devs have talked about.

 

[motowebmaster]

A few years ago, I used to run all images through a CDN using an addon.

Today, only my XF Theme Images and Avatars are done through a CDN. I'm considering this feature as a means to offload my growing amount of images, but have concerns.

I use s3cmd today, it works quite well.