Quick question

(1) Would like allocate 512GB Lun (with preallocation of 150GB) to ESX-Server & Physical-Windows server. Will they see 512GB or 150GB size of disk on hosts? If they don't see it as 150GB then whats the advantage having preallocation?

(2)  I have thin pool of 20TB; where my client is asking to 10TB to Preallocate and remaning without preallocation? Can i control preallocation upto 10TB at pool level? example--after allocation 1TBx10 luns with FULL preallocation; pool should not allow to create more preallocation on that pool.

Thanks in advance!