Question 1

What is UNMAP and why does it matter for VMware storage?

Accepted Answer

UNMAP allows a system to reclaim storage space after data is deleted, improving efficiency by returning unused capacity back to the storage pool.

Question 2

Why was UNMAP not available for NFS datastores before?

Accepted Answer

The NFS protocol does not include a native UNMAP or trim function, so ESXi had no way to communicate freed space back to the storage array.

Question 3

How does Everpure enable UNMAP for NFS datastores?

Accepted Answer

Everpure enables UNMAP through the VAAI-NAS plugin, which creates an out-of-band control path between ESXi and FlashArray to pass space reclamation requests.

Question 4

What role does the VAAI-NAS plugin play in this process?

Accepted Answer

The plugin translates guest UNMAP requests into operations the array can understand and executes them efficiently outside the main data path.

Question 5

How does this improve storage efficiency?

Accepted Answer

It allows deleted data inside virtual machines to be fully reclaimed on the array, reducing stranded capacity and improving overall utilization.

Question 6

Does this change how virtual machines handle storage?

Accepted Answer

No, virtual machines continue using standard UNMAP or trim operations, but those requests now successfully trigger space reclamation.

Question 7

How does this compare to VMFS and vVol datastores?

Accepted Answer

NFS datastores on FlashArray now provide a similar space reclamation experience, closing a long-standing gap between file and block storage.

Question 8

What are the operational benefits of this feature?

Accepted Answer

It reduces the need for manual cleanup processes, lowers resource consumption, and makes storage usage more predictable.

Author: Padhu Nagarajan

Author: Padhu Nagarajan

Offset VMware Licensing Costs by Turning Stranded NFS Space into Usable Capacity