@andrewperry yes, we replicate TrueNAS to a "standby" TrueNAS using zpool / truenas replication. Our current policy is hourly. We then (plan) to do Incremental replication of all VM's to a standby TrueNAS over weekends giving a 3 possible methods for recovery.
Currently we're running into a major drawback with VM's on TrueNAS over NFS (specifically VM's that rely on fast storage such as databases and recordings). We did not anticipate such a huge drop in performance having VHD files over NFS. We're reaching out to XCP to ask them to give us some advice as it could likely be in part due to customization we can make.