Initiate a manual failover

This page describes how to initiate a manual failover for a standard tier Memorystore for Redis instance. The manual failover feature allows you to test how normal failovers affect your application.

For an overview of this feature, see Manual failover.

Initiating a failover

Open a terminal window
Use the gcloud config command to set your default project:
```
gcloud config set core/project PROJECT_ID
```
Use the following command to initiate a failover:
```
gcloud redis instances failover INSTANCE_NAME
```

Optional data protection mode

The two available data protection modes are:

limited-data-loss mode (default).
force-data-loss mode.

To set the data protection mode, use one of the following commands:

gcloud redis instances failover INSTANCE_NAME --data-protection-mode=limited-data-loss

gcloud redis instances failover INSTANCE_NAME --data-protection-mode=force-data-loss

How data protection modes work

The limited-data-loss mode minimizes data loss by verifying that the difference in data between the primary and replica is below 30 MB before initiating the failover. The offset on the primary is incremented for each byte of data that must be synchronized to its replicas. In the limited-data-loss mode, the failover will abort if the greatest offset delta between the primary and each replica is 30MB or greater. If you can tolerate more data loss and want to aggressively execute the failover, try setting the data protection mode to force-data-loss.

The force-data-loss mode employs a chain of failover strategies to aggressively execute the failover. It does not check the offset delta between the primary and replicas before initiating the failover; you can potentially lose more than 30MB of data changes.

See Manual failover for additional information.