Understanding Blob Redundancy Options
Azure Storage provides several redundancy options to protect your blob data against hardware failures and data corruption. Choosing the right redundancy option depends on your specific requirements for durability, availability, and cost.
Locally Redundant Storage (LRS)
LRS protects your data against a hardware failure within a single data center. It copies your data synchronously three times, with each copy stored in a separate storage scale unit.
- Copies data 3 times synchronously.
- Replication within a single data center.
- Highest availability within a region.
- Lowest cost.
Zone-Redundant Storage (ZRS)
ZRS protects your data against a hardware failure within a single data center and against an entire data center or availability zone failure within a region. It copies your data synchronously across three Azure availability zones in the primary region.
- Copies data 3 times synchronously.
- Replication across 3 availability zones in a region.
- Resilient to data center outages within a region.
Geo-Redundant Storage (GRS)
GRS protects your data against a region-wide outage. It copies your data synchronously three times within a primary region, similar to LRS, and then asynchronously copies it to a secondary region.
- Synchronous replication within a primary region.
- Asynchronous replication to a secondary region.
- Protects against region-wide disasters.
Read-Access Geo-Redundant Storage (RA-GRS)
RA-GRS provides the same redundancy as GRS but also allows you to read data from the secondary region. This offers an additional layer of availability for read operations, even if the primary region is unavailable.
- Same redundancy as GRS.
- Read access to the secondary region.
- Improved read availability.
Geo-Zone-Redundant Storage (GZRS)
GZRS provides the highest level of durability and availability by combining ZRS and GRS. It copies your data synchronously across three Azure availability zones in the primary region and then asynchronously copies it to a secondary region.
- Synchronous replication across 3 availability zones in primary region.
- Asynchronous replication to a secondary region.
- Highest durability and availability.
Read-Access Geo-Zone-Redundant Storage (RA-GZRS)
RA-GZRS is similar to GZRS but includes read access to the secondary region. This offers the maximum possible durability and availability for blobs, with the added benefit of read access in the secondary region.
- Same redundancy as GZRS.
- Read access to the secondary region.
- Maximum durability and availability with read options.