2V0-621 · Question #191
An administrator needs to recover disk space on a previously-used thin provisioned virtual disk. The volumes where the administrator needs to recover the disk blocks are on VAAI-compliant storage arra
The correct answer is B. Use VMware Converter to migrate the virtual machine to a new datastore. This will recreate the D. Execute the esxcli storage vmfs unmap command.. Reclaiming previously used thin-provisioned disk blocks on VAAI-compliant arrays requires either recreating the disk via Converter migration or issuing an UNMAP command through esxcli.
Question
An administrator needs to recover disk space on a previously-used thin provisioned virtual disk. The volumes where the administrator needs to recover the disk blocks are on VAAI-compliant storage arrays. Which two actions should the administrator take accomplish this task? (Choose two.)
Options
- APerform a Storage vMotion to another volume in order to force free space recovery to occur.
- BUse VMware Converter to migrate the virtual machine to a new datastore. This will recreate the
- CIssue the vmkfstools -vmfs unmap command within the VMFS volume directory on the ESXi host
- DExecute the esxcli storage vmfs unmap command.
How the community answered
(43 responses)- A19% (8)
- B74% (32)
- C7% (3)
Why each option
Reclaiming previously used thin-provisioned disk blocks on VAAI-compliant arrays requires either recreating the disk via Converter migration or issuing an UNMAP command through esxcli.
Storage vMotion migrates the disk to another volume but does not necessarily trigger block-level reclamation on the source; it does not issue UNMAP commands to the original array.
Migrating the virtual machine to a new datastore with VMware Converter causes the tool to recreate the virtual disk from scratch, writing only current data to a new thin-provisioned disk and leaving the freed blocks unallocated on the array.
vmkfstools does not have a -vmfs unmap option; the correct tool for issuing VMFS UNMAP operations from the ESXi command line is esxcli, making this command invalid.
The esxcli storage vmfs unmap command sends SCSI UNMAP primitives to VAAI-compliant storage arrays, instructing the array to release VMFS blocks that the guest OS has already freed, directly reclaiming space at the array level.
Concept tested: Thin provisioned disk space reclamation with VAAI UNMAP
Source: https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.storage.doc/GUID-CA9CF043-9434-454E-86E7-DCA9AD9B0C09.html
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