In Vmware Esxi, there are three types of thick disks, the advantage of thick disks is performance and speed of creation, and the disadvantage is security.

• The first type: Thick Provision Lazy Zeroed
• The second type: Thick Provision Eager Zeroed
• The third type: Thin Provision

• The first type: Thick Provision Lazy Zeroed : All the space of such a disk is allocated at the time of creation, while the blocks are not cleared of data that was previously there. The first time a virtual machine accesses a new block, it is cleared. Thus, these disks are more secure, but when the block is accessed for the first time, the I / o system performance for the cleanup operation is lost.
• The second type: Thin Provision Eager Zeroed : All the space of such a disk is allocated at the time of creation, while the blocks are cleared of data that was previously there. The advantage of such a disk is performance and security, the disadvantage is a long creation time.
• The third type : Thin Provision: disks of this Type are created at a minimum size and grow as they are filled with data to the allocated volume. When a new block is selected, it is pre-cleared. These disks are the least productive.

Examples creating a vmdk virtual disk manually, when creating a virtual machine, select the "Do not create disk" option. Go to the ESXi server console via SSH and run the command in the folder with the virtual machine to create a disk:

command to create a Thin Provision disk:

vmkfstools –c 20G –d thick thick.vmdk

command to create a disk of type Thick Provision Lazy Zeroed:

vmkfstools –c 20G –d zeroedthick zeroedthick.vmdk

command to create a disk of type Thick Provision Eager Zeroed:

vmkfstools –c 10G –d eagerzeroedthick eagerzeroedthick.vmdk

Converting an existing vmdk disk type to ESXi

vmkfstools –j thin.vmdk

Converting a vmdk disk type thick to thin. Using the specified command, we get a thin disk from the vmdk disk of the thick type by copying it (the operation is long):

vmkfstools –i thick.vmdk thin.vmdk -d thin

After completing the procedure, replace the original thick disk with the newly created thin disk, and you can delete the original thick disk.