# Setting Heartbeat Datastores

While not set by default, after creating a datastore, users may choose to set it as a heartbeat datastore. Heartbeat datastores are essential for high-availability failover of VMs in the HVM Cluster. When heartbeat targets are enabled, each HVM Host continuously updates a heartbeat file, which is monitored by the other Hosts. When a Host becomes unavailable, the remaining Hosts detect this by discovering that the heartbeat file is no longer being updated. At that point, the Cluster initiates a failover process to migrate affected VMs to a new host. For greater detail on high-availability and the failover process, see [this knowledge article](https://cdn.support.hpe.com/hpesc/public/docDisplay?docId=sf000111669en_us&docLocale=en_US).

To set selected datastores as heartbeat targets, use the steps below. Multiple heartbeat datastores can be enabled for additional redundancy:

1. Navigate to Infrastructure > Clusters
2. Click on the Storage tab and then the Data Stores subtab
3. Within the Data Stores subtab, edit the desired datastore (pencil icon)
4. Mark the box labeled "HEARTBEAT TARGET
5. Click Save changes

![Editing a GFS2 datastore to make it a heartbeat datastore](https://support.hpe.com/hpesc/public/api/document/sd00008014en_us/GUID-5ACF121C-3475-4BFB-8794-ED483A879314-high.png)
