Availability zones support in Azure Web PubSub Service
Azure Web PubSub Service uses Azure availability zones to provide high availability and fault tolerance within an Azure region.
Zone redundancy is a Premium tier feature. It is implicitly enabled when you create or upgrade to a Premium tier resource. Standard tier resources can be upgraded to Premium tier without downtime.
Zone-enabled Azure regions (not all regions support availability zones) have a minimum of three availability zones. A zone is one or more datacenters, each with its own independent power and network connections. All the zones in a region are connected by a dedicated low-latency regional network. If a zone fails, Azure Web PubSub Service traffic running on the affected zone is routed to other zones in the region.
Azure Web PubSub Service uses availability zones in a zone-redundant manner. Zone redundancy means the service isn't constrained to run in a specific zone. Instead, total service is evenly distributed across multiple zones in a region. Zone redundancy reduces the potential for data loss and service interruption if one of the zones fails.