VMWARE ESXI virtual hard disk format: Thin provisioning, thick provisioning delay 0, thick provisioning zero

Thin provisioning (thin):

Thin provisioning is the amount of storage that is used now, regardless of how large the disk is allocated, and how much is used. When the client has input and output, Vmkernel first allocates the required space and clear 0 operations, that is, if the use of thin configuration when there is IO need: Wait for the allocation of space and zeroing, these two steps to complete before the operation, for the IO called frequent applications such performance will be reduced, Although storage space is saved.

That is: the actual use of how much, the allocation of how large, the maximum will not exceed the size of the actual hard disk space

Thick Provisioning Delay 0:

The default creation format, which allocates the required space for the virtual disk during the creation process. The creation will not erase any data that is kept on the physical device, there is no 0 operation, when there is an IO operation, you need to wait for the completion of the 0 operation to complete the IO,

That is , the space is allocated and the write operation is not zeroed as needed.

Thick provisioning 0 (thick):

Create a thick disk that supports cluster functionality. Allocate the required space for the virtual disk when it is created. and zero the data that is kept on the physical device. It may take longer to create a disk of this format than to create another type of disk.

That is: allocate a good space and set 0 operations, there is no need to wait for the IO operation to execute directly.

VMWARE ESXI virtual hard disk format: Thin provisioning, thick provisioning delay 0, thick provisioning zero