Storage Account (Blob / Files / Queue / Table)
Redundancy is set per storage account via the SKU (LRS/ZRS/GRS/GZRS). Geo-redundant tiers replicate to the paired region, but write access after a regional outage requires a failover you trigger yourself.
LRS (Locally Redundant Storage)
Three synchronous copies within a single physical datacenter in the primary region.
- Replication
- Synchronous
- RPO
- 0 within the datacenter
- RTO
- N/A beyond node/rack failure — a full datacenter loss is not recoverable on LRS
- Failover trigger
- N/A
Cheapest tier, and the only redundancy option for Azure managed disks beyond ZRS.
ZRS (Zone-Redundant Storage)
Three synchronous copies spread across separate Availability Zones in the primary region.
- Replication
- Synchronous
- RPO
- 0
- RTO
- Effectively 0 — reads/writes continue through a zone loss; some DNS repointing may briefly affect in-flight requests
- Failover trigger
- Automatic
Does not by itself protect against a regional disaster — pair with GZRS for that.
GRS / GZRS with Geo-priority replication
Asynchronous replication to the paired region. Azure's Geo-priority replication feature now commits to an RPO ≤15 minutes for Block Blob data specifically. Secondary-region data isn't writable — and for GRS isn't even readable — until you trigger an account failover.
- Replication
- Asynchronous
- RPO
- ≤15 min, SLA-backed — but only for Block Blobs. Files/Tables/Queues/Page Blobs replicate best-effort with no committed RPO
- RTO
- Failover process plus DNS update, typically under an hour once triggered
- Failover trigger
- Manual (customer-triggered)
RA-GRS/RA-GZRS additionally exposes the secondary as read-only during a primary outage, without needing to fail over first.
Gotchas
Geo-redundant data is not a warm standby by default
With plain GRS/GZRS, the secondary region's data is invisible until you trigger an account failover — no read, no write. Teams that assume geo-redundancy alone gives them instant regional continuity are wrong; use RA-GRS/RA-GZRS if you need read access before failing over, and either way the failover itself is a manual action.
The 15-minute RPO guarantee is Block Blob only
Geo-priority replication's SLA-backed ≤15 min RPO applies to Block Blob storage. Azure Files, Table Storage, Queue Storage, and Page Blobs on the same GRS/GZRS account replicate on a best-effort basis with no committed number — don't assume the headline RPO covers every workload in the account.
Managed disks don't support cross-region redundancy at all
Managed disks support LRS and (with limitations) ZRS only — no GRS/GZRS option exists. VM disk resiliency beyond a zone is Azure Site Recovery's job, not the storage layer's.