I like the feature of Hyper-V replica – but sometimes if you are configuring it quickly you might fail to set the right replication interval (by default 5 minutes). There is a possibility in PowerShell to change the interval so for example if you have configured your replication to happen every 5 minutes and you want to change that to 30 seconds you can do it by using this cmdlet (this one will change all current replicas to 30 seconds – you can do it for individual replication also):

Get-VMReplication | Set-VMReplication -ReplicationFrequencySec 30