Replication job to a VVOL target will fail with the error below:
Task.<VM name>.vm-<vm-ref> will contain following error:
[TIMESTAMP] <21> Info [AP] (5e06) disconnecting
[TIMESTAMP] <55> Error [AP] (5e06) error: VDDK error: 7 (A file access error occurred on the host or guest operating system). Value: 0x0000000000000007
[TIMESTAMP] <55> Error Failed to write to a virtual disk
Due to a change in VMware vSphere 6.0 Update 1, replication to VVol datastores is no longer possible with either Veeam or vSphere replication. This article will be updated in case more recent VMware vSphere updates fix this newly introduced issue.
Here is an official statement from VMware VDDK release notes:
Avoid creating snapshots for restore on VVol datastores. Due to Virtual Volume (VVol) implementation in the vSphere 6.0 release, VMware recommends against creating a snapshot (then reverting and deleting it) when restoring files on a VVol datastore. This is because writing to a non-leaf disk (such as a snapshot backing file) is considered a layering violation and throws an error on many VVol storage devices. Writing to the leaf disk of the snapshot is not a layering violation. The restore snapshot remains mandatory for SAN transport, which is not supported on VVol datastores anyway.
Replication job to VMware Virtual Volumes (VVols) is no longer supported.