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With the eagerzeroedthick allocation mechanism (known as Thick Provision Eager Zeroed in the vSphere Client, or EZT), space that is required for the virtual disk is completely allocated and written to at creation time. This condition leads to a full reservation of space on the VMFS datastore and on the underlying PowerMax device. So, it takes longer to create disks in this format than to create other types of disks.
A single 90 GB virtual disk that uses the eagerzeroedthick allocation method is shown in Figure 99. The datastore browser reports the virtual disk as consuming the entire 90 GB on the volume, like zeroedthick and thin.
On most thin arrays, eagerzeroedthick causes an equal amount of space to be reserved on the array as VMware. However, the PowerMax does not work this way. The eagerzeroedthick virtual disk resides on thin device 003A and as highlighted in Figure 100 no space is consumed. The reason is addressed in the next sections.