(admin manual) Document S3 compatibility requirements

[joshtrichards]

We should try to document the knowable requirements we have for S3 in a generic manner.

We should perhaps mention what we test again (i.e. MinIO).

Then also consider including specifics for some of the more common platforms/providers (to be added to over time).

Some platforms and providers are not compliant enough with AWS S3 to work with NC. Others are compatible, but only if certain changes are made to their default configuration. Others work fine but sometimes use different terminology.

This is becoming an issue as people experiment with using the S3 support with more platforms.

• B2 S3 mode seems to work as-is (these days)
• GCS requires switching from what they call "Uniform" mode to ACL mode
• etc.

Various related Issues:

(to be added)

e.g. https://github.com/nextcloud/server/issues/35364

[col-panic]

A remark to this:

We have S3 as primary storage using minio, and every time there is a problem, you only face an "Internal Server Error" page. We would very much like a page that does not only say "Internal Server Error" but that there is a specific problem with the s3 storage.

In addition, if S3 is the primary storage, an inclusion into php occ status would also be of much interest. (E.g. someone uses the status endpoint to do docker healthcheck https://github.com/nextcloud/docker/issues/676#issuecomment-1495671735)

Just before I had 2 errors in the S3 which weren't obvious, the first one being

• <Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calcul which needed a change of OBJECTSTORE_S3_LEGACYAUTH to false and then
• <Error><Code>XMinioStorageFull</Code><Message>Storage backend has reached its min which was simply due to the target server not having enough spare space

All of these led to a mere Internal Server Error

[joshtrichards]

We would very much like a page that does not only say "Internal Server Error" but that there is a specific problem with the s3 storage.

In general we don't display much info via the web if something fails fatally since unauthenticated users can see it. And admins have access to logs which is where one should look when seeing an "Internal server error". :)