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Druva Documentation

Impact of Thick and Thin Provisioned VMware Disk on the current source


This article provides a clear understanding of the data backup and restore size using Thick or Think disk for VMware backups.

Assumption: The example in this article has 1 VMDK for each virtual machine.

Impact on Backup

Below table shows the backup size consumed by the storage for Thick and Thin Disk.

Disk Provisioning = Thick (Lazy / Eager Zero) Disk provisioning = Thin
VM disk size = 150 GB VM disk size = 150 GB
Total User data on Disk = 20 GB Total User data on Disk = 7.42 GB
Current Source shows = 150 GB Current Source shows = 7.42 GB
Source + Changes = 150 GB Source + Changes = 7.42 GB

The above table indicates:

  • When the VM disk is Thick provisioned, Phoenix shows the size of the Disk. (This may vary if the disk size is increased or reduced from VM settings.)

  • When the VM disk is Thin provisioned, Phoenix shows the actual data as current source present on disk and not the complete disk size.


Note: If the datastore type is any of "NFS", "NFS41" or "NFS42" file system, then the Current Source size is equal to VM disk size.

Impact on Restore

For restore:

  • Both the Thick and Think disks show the actual size of the disk in the restore window.

  • The data restore size in the Thin disk is the data that was backed up. (For example, if 7.42 GB/150 GB was backed up, then the estimated size is 150 GB, but the restore size is 7.42 GB only.)

    The estimation phase shows the actual disk size for the Thin disk.


    The actual restore job log shows 7.42 GB only.


See also

Restore VMware virtual machine to an alternate location

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