Thin-provisioned virtual disks — SDelete alternative to reclaiming space

At a high level, thin provisioning is the act of using virtualization technology to give the appearance of more physical resource than is actually available. It can refer to any physical resource, such as real memory or physical disk drives. Whatever task the computer is trying to do, it behaves as if it were interacting with a real, physical device.

In the case of a disk drive, when you create a virtual machine, a certain amount of storage space on a datastore is provisioned to virtual disk files. When you need to save storage space, you can create a virtual disk in thin provisioned format. The thin provisioned virtual disk starts small and grows as more disk space is required.

Over provisioning is a common issue in data centers due to thin provisioning. While thin provisioning saves space, there is a performance hit and also an increase in the probability of running out of space in the storage group. Administrators often turn to the SDelete (Secure Delete) command line utility to recover space. SDelete deletes existing files and erases any file data that exists in the unallocated portions of a disk (including files that you have already deleted or encrypted). With SDelete, you can also overwrite the contents of free space on your disk. An alternative to SDelete for recovering space for thin-provisioned virtual disk is PerfectDisk’s Zero Fill.

The steps involved in the 2 scenarios for Physical-to-Virtual are outlined here.

With SDelete

  1. Defrag with Windows Built-in Defrag.
  2. Shut down applications and services that may require disk space.
  3. Run SDelete command line manually to zero out all free space on drive.
  4. Restart applications and services.
  5. Repeat steps 2 – 4 for all drives.
  6. Run appropriate hypervisor migration tool (e.g. VMotion, Live Migration, XenMotion).
  7. Maintain script code and repeat above procedure at regular intervals.

With PerfectDisk Zero Fill

  1. With a single click, consolidate free space and move all files to beginning of the drive.
  2. Run appropriate hypervisor migration tool (e.g. VMotion, Live Migration, XenMotion).
  3. If desired, set up an automated schedule to regularly move files to beginning of disk and zero fill space.

PerfectDisk Zero Fill — the simple, powerful and automated alternative to SDelete. Smarter.

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Category: PerfectDiskStorageVirtualization


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