Forum Discussion

LouisT's avatar
LouisT
Tin Contributor
Dec 20, 2025

Understanding Storage Account replication downtime

I have a Storage account that's used as a CDN to host a  lot of generally small files which occupy about 2GB. This is a small but critical part of our application which is used heavily by our app but...
Data + Storage
Jamony's avatar
Jamony
MCT
Jun 26, 2026

The "online conversion" guidance is in the storage redundancy migration article. In the portal, this is the Redundancy blade on the storage account; with CLI/PowerShell there are also migration/update paths depending on the current and target redundancy options. Whether LRS to GZRS is available directly depends on account type, region support, features such as archive tier/NFS, and current account state.

 

For the DR requirements, there are two important distinctions:

 

1. Converting redundancy should normally be planned separately from failover testing.

2. Regional failover is not completely invisible. During failover, Azure updates DNS so the secondary becomes the new primary endpoint. After completion, clients can write to the new primary, but there is a temporary outage during the operation. Planned failover for GZRS/RA-GZRS is typically around an hour; unplanned failover can involve data loss because replication is asynchronous.

 

If the application truly cannot tolerate downtime or failover windows, storage-account geo-redundancy alone is not enough. You would need an app-level multi-region design, potentially with separate storage accounts and routing logic/CDN failover.

 

Useful docs:

https://learn.microsoft.com/azure/storage/common/redundancy-migration

https://learn.microsoft.com/azure/storage/common/storage-disaster-recovery-guidance

https://learn.microsoft.com/azure/storage/common/storage-failover-customer-managed-planned