To determine the minimum amount of HDD capacity required for the workload after converting thick provisioned disks to thin provisioned disks, we need to consider the active working set and the typical overhead for thin provisioning.

Current Capacity:

The prospect currently has 8500GB (8.5TiB) of provisioned capacity.

Active Working Set:

The total active working set for the cluster is determined to be 1TB.

Thin Provisioning:

Thin provisioning reduces the need for physical storage because it allocates storage on-demand rather than reserving the full capacity upfront.

Nutanix typically advises planning for additional overhead to accommodate metadata, snapshots, and potential growth.

Calculation:

The rule of thumb for thin provisioning overhead is approximately 2-3 times the active working set to ensure adequate capacity for metadata and additional data growth.

Using the higher end of the multiplier (3 times):

1TB (active working set)×3=3TB1 \text{TB (active working set)} \times 3 = 3 \text{TB}1TB (active working set)×3=3TB

Conclusion:

Therefore, the minimum HDD capacity required for the workload when thin provisioning is applied would be around 3.0TiB.

References:

Nutanix Sizing Guidelines.

Nutanix Documentation on Thin Provisioning and Storage Optimization.