Skip to content

Get-S2DCapacityWaterfall

Computes the 7-stage theoretical capacity waterfall from raw physical to final usable capacity.


Synopsis

Extracts inputs from the live cluster session (physical disks, pool, volumes) and computes the 7-stage waterfall model. The waterfall is entirely theoretical — it represents what the hardware can deliver, not what has been provisioned.

Stage deductions are applied in sequence:

Stage Description Deduction
1 Raw Physical Pool-member capacity-tier disk total
2 After Format File system and partition overhead (~0.9%)
3 After Pool Overhead S2D pool management overhead (~1%)
4 After Reserve Rebuild reserve: min(NodeCount, 4) × one drive
5 After Infrastructure Azure Local system volumes (UserStorage, SBEAgent, etc.)
6 After Resiliency Resiliency factor deduction (÷ NumberOfDataCopies)
7 Usable Capacity Final available capacity for workload volumes

Requires an active session from Connect-S2DCluster.

This cmdlet takes no parameters.


Syntax

Get-S2DCapacityWaterfall

Outputs

S2DCapacityWaterfall — contains the full waterfall model.

Key properties:

Property Description
Stages Array of S2DWaterfallStage objects (one per stage)
UsableCapacity Final Stage 7 usable capacity as S2DCapacity
RawCapacity Stage 1 raw capacity as S2DCapacity
ResiliencyFactor The NumberOfDataCopies used in Stage 6
NodeCount Number of cluster nodes contributing to the model
ReserveStatus Adequate or Critical based on reserve vs pool free
BlendedEfficiencyPercent Usable / raw capacity efficiency percentage

Each S2DWaterfallStage:

Property Description
StageNumber 1–7
StageName Human-readable stage name
Capacity Cumulative capacity at this stage as S2DCapacity
Deducted Amount deducted from the previous stage as S2DCapacity
Description Explanation of the deduction

Examples

Compute and display:

Connect-S2DCluster -ClusterName "tplabs-clus01" -Credential $cred
Get-S2DCapacityWaterfall

Show the stage table:

Get-S2DCapacityWaterfall | Select-Object -ExpandProperty Stages | Format-Table StageNumber, StageName, Capacity, Deducted

Get the usable capacity number:

$waterfall = Get-S2DCapacityWaterfall
"Usable: $($waterfall.UsableCapacity.Display)"

See Capacity Math for a detailed explanation of each stage formula, and Collectors / Capacity Waterfall for the full pipeline context.