Explanation
Why the waste happens and who it affects.
While suitable for high-availability production systems, this level of resilience may be unnecessary for development, testing, or lower-impact workloads.
Using RA-GRS without a business requirement results in avoidable costs. Downgrading to LRS or ZRS - where appropriate - can significantly reduce monthly backup storage spend. Backup frequency and retention stay the same, but switching to LRS or ZRS disables geo-restore as soon as the change is made. The change applies only to new backups (existing backups stay in the old storage until their retention expires) and can take up to 48 hours to apply. Hyperscale backup redundancy can only be set at creation, so changing it requires a database copy or geo-replication.
Billing model
The pricing dimensions that drive this cost.
- Backup storage is charged per GB-month, but vCore databases are billed only for backup storage above the maximum data size (in the DTU model, PITR backup storage is included in the database price), so savings apply to that excess and to LTR backup storage
- RA-GRS (geo-redundant) storage is the default; geo-zone-redundant storage (GZRS) is also offered, and LRS is the least expensive option
- LRS (Locally Redundant Storage) and ZRS (Zone Redundant Storage) are lower-cost alternatives
- Changing backup storage redundancy lowers the per-GB rate for billable backup storage without affecting primary database performance
How to detect
4 checks to find it in your estate.
- Review backup redundancy settings for Azure SQL databases
- Identify databases with RA-GRS enabled by default
- Determine whether geo-redundant backup storage is a business or compliance requirement
- Validate whether LRS or ZRS would be sufficient based on workload criticality and risk tolerance
How to fix
4 ways to remove the waste.
- For non-critical or non-regulated workloads, change the backup redundancy setting to LRS (or ZRS where supported)
- Document any exceptions where RA-GRS must be retained for compliance
- Incorporate backup configuration reviews into provisioning and governance processes
- Monitor backup storage cost trends following changes to confirm savings
Documentation
Vendor references for pricing and configuration.