Starting May 1, 2026, all Azure Service Bus Premium
namespaces deployed in regions with Availability
Zone support now qualify for a 99.99% uptime SLA.
Premium is the tier customers choose for their most important workloads, and
this update brings the SLA in line with the zone-redundant infrastructure those
namespaces already run on. Previously, the 99.99% SLA required partitioned
namespaces to be enabled. That requirement has been removed - any Premium
namespace in an AZ region now receives the higher SLA automatically.
Availability Zones are physically separate datacenters
within an Azure region, each with independent power, cooling, and networking. A
Premium namespace deployed in an AZ region is automatically replicated across
multiple zones, so the messaging service stays available even if a full
datacenter goes offline. No configuration changes are required for existing
deployments to benefit from the higher SLA.
Partitioned namespaces remain fully supported for workloads
that need higher throughput through multi-broker distribution. The change is
purely about SLA eligibility - partitioning is no longer a prerequisite for the
99.99% commitment.
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