--- title: Returning Traffic Safely: An Active/Active ARC Region... description: A detailed game-day report on safely restoring traffic to a recovered AWS region in an active/active setup using AWS Application Recovery Controller (ARC). The... canonical: https://daily.dev/posts/returning-traffic-safely-an-active-active-arc-region-switch-game-day-wjmfn8dhg twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Returning Traffic Safely: An Active/Active ARC Region Switch Game Day | daily.dev og:description: A detailed game-day report on safely restoring traffic to a recovered AWS region in an active/active setup using AWS Application Recovery Controller (ARC). The... og:url: https://daily.dev/posts/returning-traffic-safely-an-active-active-arc-region-switch-game-day-wjmfn8dhg og:image: https://api.daily.dev/og/posts/WjMfN8dHG.png og:image:alt: Returning Traffic Safely: An Active/Active ARC Region Switch Game Day og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Returning Traffic Safely: An Active/Active ARC Region Switch Game Day **[Medium](https://daily.dev/sources/medium_js)** · 14 min read · 0 upvotes · 0 comments ## Summary A detailed game-day report on safely restoring traffic to a recovered AWS region in an active/active setup using AWS Application Recovery Controller (ARC). The author ran a 1,000 TPS Gatling load test across ECS Fargate services in us-west-2 and us-east-2 with DynamoDB Global Tables. The key insight is that failback is harder than failover: blindly switching back to latency-based Route 53 routing can overwhelm cold infrastructure. The safe pattern involves capturing the last observed regional traffic split, using weighted DNS as a gradual restoration bridge with capacity gates (requiring 90% ALB-healthy targets before each weight increase), pre-scaling both regions before returning to latency policy, and making DNS record changes atomically. The full activation plan completed in ~5 minutes with only 25 failures out of 915,175 requests (0.0027% error rate). The post also compares this approach to active/passive ARC region switches and zonal shifts, noting each has distinct use cases and tradeoffs. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [A successful 1,000 TPS checkout game day: pilot light to full scale with AWS ARC Region switch](https://daily.dev/posts/a-successful-1-000-tps-checkout-game-day-pilot-light-to-full-scale-with-aws-arc-region-switch-of9balhwp) · Medium · 0 upvotes · 0 comments - [ARC Region switch adds three new capabilities: post-recovery workflows, RDS orchestration and AWS provider support for Terraform](https://daily.dev/posts/arc-region-switch-adds-three-new-capabilities-post-recovery-workflows-rds-orchestration-and-aws-pr-xre7qvfhg) · AWS · 0 upvotes · 0 comments - [High Availability Is Not Resilience: Why Cloud Systems Fail When It Matters Most](https://daily.dev/posts/high-availability-is-not-resilience-why-cloud-systems-fail-when-it-matters-most-smooc60cw) · InfoQ · 1 upvotes · 0 comments - [How when AWS was down, we were not](https://daily.dev/posts/how-when-aws-was-down-we-were-not-2z7ljw5ij) · Hacker News · 1 upvotes · 0 comments - [ARC Region switch adds Amazon Aurora scaling and Amazon Neptune global database failover](https://daily.dev/posts/arc-region-switch-adds-amazon-aurora-scaling-and-amazon-neptune-global-database-failover-pmooiuc2k) · AWS · 0 upvotes · 0 comments --- Tags: [#aws](https://daily.dev/tags/aws), [#aws-dynamodb](https://daily.dev/tags/aws-dynamodb) [View this post on daily.dev](https://daily.dev/posts/returning-traffic-safely-an-active-active-arc-region-switch-game-day-wjmfn8dhg) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Returning Traffic Safely: An Active/Active ARC Region Switch Game Day","url":"https://daily.dev/posts/returning-traffic-safely-an-active-active-arc-region-switch-game-day-wjmfn8dhg","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/returning-traffic-safely-an-active-active-arc-region-switch-game-day-wjmfn8dhg"},"datePublished":"2026-07-28T07:32:41.302Z","dateModified":"2026-07-28T07:34:14.649Z","description":"A detailed game-day report on safely restoring traffic to a recovered AWS region in an active/active setup using AWS Application Recovery Controller (ARC). 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