| Single write region | Enabled | In case of outage in a read region when not using strong consistency, all clients will redirect to other regions. No read or write availability loss. No data loss. When using strong consistency, read region outage can impact write availability if fewer than two read regions remaining.<p/> In case of an outage in the write region, clients will experience write availability loss until Cosmos DB automatically elects a new region as the new write region according to your preferences. If strong consistency level is not selected, some data may not have been replicated to the remaining active regions. This depends on the consistency level selected as described in [this section](consistency-levels.md#rto). If the affected region suffers permanent data loss, unreplicated data may be lost. | During the outage, ensure that there are enough provisioned RUs in the remaining regions to support read traffic. <p/> Do *not* trigger a manual failover during the outage, as it will not succeed. <p/> When the outage is over, you may move the write region back to the original region, and re-adjust provisioned RUs as appropriate. Accounts using SQL APIs may also recover the non-replicated data in the failed region from your [conflicts feed](how-to-manage-conflicts.md#read-from-conflict-feed). |
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