ARC Region Switch assists customers in automating failover of multi-Region applications to meet recovery time objectives during Regional impairments. The newly announced Lambda event source mapping execution block automates the enablement and disablement of Lambda event source mappings in activating and deactivating Regions, eliminating manual toggling to prevent duplicate event processing in active-passive workloads.
This block can be sequenced in plans to first disable event processing in the failing Region and then enable it in the recovery Region, with an option for "ungraceful" mode allowing override when the deactivating Region is impaired. It also supports cross-account failover handling. ARC Region Switch and the new event source mapping feature are available in all commercial AWS Regions.
Source & further reading
ARC Region switch adds Lambda event source mapping execution block for event handling during failover ↗Source published 2026-05-14. This report was prepared with AI assistance from the linked primary-source material. Claims and limitations should be checked against the original announcement or research.