Thin provision ESXi VMDK slower speed

Noob here.

I have 3 file systems (lets call them RAID, DATA, and SSHD). I no longer need the RAID 1, so I degraded it. I deleted the files on the VMDK and added it back into ESXi but this time as Thin Provisioned. I added the physical disk into OMV (looks like it wrote zero's to it) and ran some comparison tests using SMB. I did the testing on a VM that has access to OMV file systems, here are my results:

-RAID to SSHD, avg 100MB/s
-SSHD to DAS of VM, 80-200MB/s Wow!
-RAID to DAS of VM, 100MB/s.

Everything no matter how I transferred data was about 100-300MB/s. BUT the newly created file system is only transferring at about 50MB/s writing to it. Copying files from the new DATA store is acceptable (around 200MB/s)

Q) Is Thin Provision a nono when it comes to OMV and ESXi? I hope not because I would like to start using vSphere Data Protection but the 4TB VMDK is too big to run a backup.
Note: I read a post about installing LVM plug-in and use iSCSI target but that's Greek to me (again noob).

Thank you for your time,
-Dave-

Do you have any suggestions? The OS that OMV runs on is thick, actually all my drives for OMV are think except for the recently added one. Also, I cannot use Apt-get any longer.

I seen someone recommend the following in a different post but I have no idea what he means by adding a target: install the LVM plugin and use it to create your thin provisioned iscsi targets. Does OMV support thin provisioning