You can store replica VMs on a separate datastore or on the same datastores as the clones. These configurations affect the availability of the pool in different ways.
When you store replicas on the same datastores as the clones, to enhance availability, a separate replica is created on each datastore. If a datastore becomes unavailable, only the clones on that datastore are affected. Clones on other datastores continue to run.
When you store replicas on a separate datastore, all clones in the pool are anchored to the replicas on that datastore. If the datastore becomes unavailable, the entire pool is unavailable.
To enhance the availability of the desktop pool, you can configure a high-availability solution for the datastore on which you store the replicas.