We are excited to announce the general availability of graceful failovers in Azure DocumentDB.<\/p>\n
Not every region switch is because of availability loss. Whether you’re migrating your primary workload to a different Azure region or proactively moving ahead of a forecasted application-level upgrade, you need a failover mechanism that prioritizes data integrity over speed. One that lets you move deliberately, not reactively.<\/p>\n
With Graceful Failover, you initiate a controlled promotion of your replica cluster to read-write and the service guarantees that every write committed on the primary is replicated before the switch happens. No data loss. No surprises.<\/p>\n
How It Works<\/strong><\/p>\n Azure DocumentDB’s cross-region replication keeps a replica cluster in a secondary Azure region which is continuously and asynchronously synchronized with your primary. Under normal conditions, the replica trails the primary by a small window (usually in milliseconds) to avoid impacting write performance on the primary, but close enough to make a clean handoff possible.<\/p>\n When you trigger a Graceful Failover, Azure DocumentDB executes a precise, ordered sequence:<\/p>\n The result is a clean, zero-data-loss region switch. Your application continues operating against the global read-write connection string, which automatically updates to point to the newly promoted cluster with no connection string change required.<\/p>\n Choosing the Right Failover Mode<\/strong><\/p>\n Graceful Failover is one of three ways a replica cluster can assume the read-write role. Here’s how they compare:<\/p>\n Graceful Failover is the right choice when:<\/p>\n If an actual regional outage occurs and the primary is unreachable, Forced Promotion or Service-Managed Failover are the appropriate mechanisms. Graceful Failover requires the primary to be reachable in order to drain the queue and is thus not the right choice in that scenario.<\/p>\n What You Need to Use It<\/strong><\/p>\n Graceful Failover requires cross-region replication to be configured. To use it:<\/p>\n No application-side changes are needed beyond using the global connection string.<\/p>\n In-Region HA and Cross-Region DR: The Full Picture<\/strong><\/p>\n Graceful Failover addresses planned or proactive region switches, but it works alongside and not instead of in-region high availability (HA). Here’s how the layers fit together:<\/p>\n Running all three in combination gives you comprehensive coverage across failure scenarios at every scale.<\/p>\n\n
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\n Mode<\/strong><\/td>\n Trigger<\/strong><\/td>\n Zero Data Loss<\/strong><\/td>\n Automatic<\/strong><\/td>\n<\/tr>\n<\/thead>\n\n \n Graceful promotion<\/strong><\/td>\n User-initiated<\/td>\n \u2705<\/td>\n \u274c<\/td>\n<\/tr>\n \n Forced promotion<\/strong><\/td>\n User-initiated<\/td>\n \u274c<\/td>\n \u274c<\/td>\n<\/tr>\n \n Service-managed failover<\/strong><\/td>\n Automatic (Azure DocumentDB)<\/td>\n \u274c<\/td>\n \u2705<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \n
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