A VM needs to be powered on during the initial sync. Once completed, the VM can be powered off without hampering replication. Checkpoints will continue to be sent but they will contain no data as the disks of the VM aren’t changing. Also a powered-off VM can be vMotioned to a new physical host as long as the physical host you are migrating to has a VRA on it.

Although Zerto IRP doesn’t directly monitor the power states of VMs, if a VM is powered off during a sync this will trigger an alert to be generated.