Back when we first started with Zerto, there was a size restriction for single disks for replication. Does that still apply? What is the restriction?
There are still some hypervisor based limitations on disk size. Please see the Zerto Administration Guide, starting on page 243, for more information.
Zerto Administration Guide – http://s3.amazonaws.com/zertodownload_docs/Latest/Zerto%20Virtual%20Manager%20vSphere%20Administration%20Guide.pdf
Does this help?