Hello ,
On the Thick Disk Type the blocks on the physical drives are allocated in advance while creating the disk. This task can only be achieved when Hardware Acceleration is enabled. Nowdays most of the SAN supports Hardware Acceleration. Please check with your SAN Vendor if this can be enabled.
Also without the Hardware Acceleration the Thick disks cannot be provisioned. You can continue using the Thin Disk type as the performance on both of them is same. With thin disk we only need to be cautious with over provisioning.