Reliability in Azure Bot Service
When you create an application (bot) in Azure, you can choose whether or not your bot resource will have global or local data residency. Local data residency ensures that your bot's personal data is preserved, stored, and processed within certain geographic boundaries (like EU boundaries).
Availability zone support is not enabled for any standard channels in the regional bot service.
This article describes reliability support in Azure Bot Service, and covers both regional reliability with availability zones and cross-region resiliency with disaster recovery for bots with local data residency. For a more detailed overview of reliability in Azure, see Azure reliability.
For more information on deploying bots with local data residency and regional compliance, see Regionalization in Azure Bot Service.
Availability zone support
Azure availability zones are at least three physically separate groups of datacenters within each Azure region. Datacenters within each zone are equipped with independent power, cooling, and networking infrastructure. In the case of a local zone failure, availability zones are designed so that if the one zone is affected, regional services, capacity, and high availability are supported by the remaining two zones.
Failures can range from software and hardware failures to events such as earthquakes, floods, and fires. Tolerance to failures is achieved with redundancy and logical isolation of Azure services. For more detailed information on availability zones in Azure, see Regions and availability zones.
Azure availability zones-enabled services are designed to provide the right level of reliability and flexibility. They can be configured in two ways. They can be either zone redundant, with automatic replication across zones, or zonal, with instances pinned to a specific zone. You can also combine these approaches. For more information on zonal vs. zone-redundant architecture, see Build solutions with availability zones.
For regional bots, Azure Bot Service supports zone redundancy by default. You don't need to set it up or reconfigure for availability zone support.
- Your bot must be regional (not global).
- Currently, only the "westeurope" region supports availability zones.
Zone down experience
During a zone-wide outage, the customer should expect a brief degradation of performance, until the service's self-healing rebalances underlying capacity to adjust to healthy zones. This isn't dependent on zone restoration; it's expected that the Microsoft-managed service self-healing state compensates for a lost zone, using capacity from other zones.
Cross-region disaster recovery in multi-region geography
Azure Bot Service runs in active-active mode for both global and regional services. When an outage occurs, you don't need to detect errors or manage the service. Azure Bot Service automatically performs autofailover and auto recovery in a multi-region geographical architecture. For the EU bot regional service, Azure Bot Service provides two full regions inside Europe with active/active replication to ensure redundancy. For the global bot service, all available regions/geographies can be served as the global footprint.