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12 changes: 12 additions & 0 deletions pages/clustering/high-availability.mdx
Original file line number Diff line number Diff line change
Expand Up @@ -384,6 +384,18 @@ server that coordinator instances use for communication. Flag `--instance-health
check the status of the replication instance to update its status. Flag `--instance-down-timeout-sec` gives the user the ability to control how much time should
pass before the coordinator starts considering the instance to be down.


Users can also choose whether failover to the async replica is allowed by using the following query:

```
SET COORDINATOR SETTING 'sync_failover_only' TO 'true'/'false' ;
```

By default, the value is `true`, which means that only sync replicas are candidates in the election. When the value is set to `false`, the async replica is also considered, but
there is an additional risk of experiencing data loss. However, failover to an async replica may be necessary when other sync replicas are down and you want to
manually perform a failover.


<Callout type="info">

Consider the instance to be down only if several consecutive pings fail because a single ping can fail because of a large number of different reasons in distributed systems.
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