Missing S3/GCS/Azure parameters in URI Formats of External Storage Services

Change Request

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.

(First of all why do we have both https://docs.pingcap.com/tidb/stable/backup-and-restore-storages and https://docs.pingcap.com/tidb/stable/external-storage-uri? The BR one should be moved into the general one, as the latter failed to describe the authentication procedure.)

Several parameters are undocumented:

• s3://?region= — clearly an oversight.
• s3://?provider= — the provider option is sometimes required to solve some subtle compatibility problem when using a non-AWS endpoint.
• s3://?object-lock-enabled= (pingcap/tidb#37392) — will be automatically checked in BR, so likely intended to be undocumented.
• gcs://?endpoint=
• azblob://?endpoint=

2. Describe your suggestion or addition.

Document at least s3://?region=&provider=.

3. Provide some reference materials (such as documents and websites) if you could.

Start by comparing the backup-and-restore-storages and external-storage-uri documentation pages named in the issue. Document at least the S3 region and provider parameters, and determine how the requested GCS and Azure endpoint details and authentication procedure fit across those pages; done means the relevant URI parameters are described without duplication.