Get-Capacity

A PowerShell 7 script that reports Azure VM SKU availability, zone restrictions, and family quota for a given subscription and region. It is built for capacity investigations — quickly answering "can I deploy this VM size here, and if not, why?"

What it does

For every virtualMachines SKU offered in the target region, the script combines two Azure data sources:

• Get-AzComputeResourceSku — which zones a SKU is offered in and any subscription restrictions (region-level or zone-level).
• Get-AzVMUsage — the current usage and limit (quota) for each VM family.

It then produces, per SKU, a clear verdict (Available / Partial / Unavailable), the usable vs. offered zones, the reason for any restriction, and the family quota.

Requirements

• PowerShell 7.0+ (enforced via #Requires -Version 7.0).
• The Az PowerShell module (Az.Accounts, Az.Compute).
• An authenticated Azure session (Connect-AzAccount) with read access to the target subscription.

Parameters

Parameter	Description
-SubscriptionId	Subscription to analyse, by id. Mutually exclusive with -SubscriptionName.
-SubscriptionName	Subscription to analyse, by display name. Mutually exclusive with -SubscriptionId.
-Region	Azure region/location to analyse (e.g. westeurope). Required.
-Family	Optional VM SKU family filter. Supports wildcards (e.g. standardDSv3Family, *Dsv5*).
-ListFamilies	Lists the distinct SKU family ids in the region (with an example SKU each) and exits. Honours -Family.

Exactly one of -SubscriptionId / -SubscriptionName must be supplied.

Usage

Analyse a whole region by subscription id:

.\get-capacity.ps1 -SubscriptionId <guid> -Region westeurope

Analyse by subscription display name:

.\get-capacity.ps1 -SubscriptionName "My Subscription" -Region westeurope

Discover the family names available in a region (to find the value for -Family):

.\get-capacity.ps1 -SubscriptionId <guid> -Region westeurope -ListFamilies

Limit the analysis to one family (wildcards supported):

.\get-capacity.ps1 -SubscriptionId <guid> -Region westeurope -Family *Dsv5*

Family hints: Dv5 is standardDv5Family, Dsv5 is standardDSv5Family. Use -ListFamilies if unsure of the exact id.

Output

The on-screen table is a compact view with these columns:

Column	Meaning
Family	The VM SKU family id.
SKU	The VM size (sorted numerically within a family, e.g. D2 before D16).
Quota	used/limit (remaining left) for the family in the region.
Availability	Available, Partial (some zones usable), or Unavailable.
Zones	Usable vs. offered zones, e.g. 1 usable (offered: 1,2,3) or none usable (offered: 2).
Detail	A concise reason for any restriction (region block, restricted zones, reason codes, etc.).

Reading the zone information

Two distinct zone sets are involved and the output keeps them separate:

• Offered zones come from the SKU's LocationInfo — the zones where Azure offers the SKU in that region.
• Restricted zones come from the subscription restriction (RestrictionInfo.Zones) — a subscription-wide list that may include zones the SKU isn't even offered in.

A SKU is Unavailable when the region is blocked outright, or when every offered zone is restricted (even if other restricted zones aren't relevant). 0/0 (0 left) quota means the family has no quota assigned.

Full detail

The script emits rich PSCustomObjects; the table only shows a subset. Capture the output for the complete breakdown (including SupportedZones, AvailableZones, RestrictedZones, RestrictedRegions, QuotaAssigned, QuotaUsed, QuotaRemaining):

$report = .\get-capacity.ps1 -SubscriptionId <guid> -Region westeurope
$report | Export-Csv capacity.csv -NoTypeInformation
$report | Format-List   # per-SKU detail

Notes

• The script sets Set-StrictMode -Version Latest and $ErrorActionPreference = 'Stop', so it fails fast on the first error (e.g. an invalid subscription or region).
• Quota matching uses an O(1) hashtable keyed on the family id rather than a per-SKU scan of the usage list.
• ForEach-Object -Parallel was evaluated but intentionally not used: the per-SKU work is microsecond-level in-memory string handling, so runtime is dominated by the two Azure REST calls, not the loop.