Redundancy reference pages overgeneralize RA-GRS and RA-GZRS without the Azure Files exception

[yeongseon]

Summary

The generic redundancy pages present RA-GRS and RA-GZRS as if they were normal storage-wide options, but this repository also teaches Azure Files and does not surface the important Azure Files exception in the redundancy references.

Why this is a problem

Current Microsoft Learn is explicit that Azure Files:

• supports geo-redundancy only as GRS or GZRS for eligible HDD file shares
• does not support RA-GRS or RA-GZRS
• if a storage account is configured with RA-GRS or RA-GZRS, Azure Files is billed/configured as GRS or GZRS

In this repo, readers can move from Azure Files-oriented content into generic redundancy pages that list:

• RA-GRS
• RA-GZRS
• Read from secondary
• 99.99% read

without any Azure Files caveat.

That makes it easy for a file-share reader to infer that Azure Files inherits the same read-access secondary behavior, which is not true.

Affected files

• docs/platform/redundancy-and-durability.md
• docs/reference/redundancy-options.md

Suggested direction

Keep the generic storage-account view, but add an explicit note that service support differs and Azure Files is a notable exception:

• Azure Files doesn't support RA-GRS / RA-GZRS
• geo-redundancy for Azure Files is limited to GRS / GZRS on eligible share types
• read access to the secondary region for Azure Files requires failover rather than RA-* behavior

Sources

• https://learn.microsoft.com/en-us/azure/storage/files/files-redundancy
• https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy