PowerShell: NetApp – Discover Every Volume Over 80 Percent Capacity

cluster1::> security login create -vserver <cluster-admin-svm> -user-or-group-name capacity-report -application http -authentication-method password -role readonly

.\Get-NetAppVolumesOverThreshold.ps1 -Clusters "cluster1-mgmt.example.com", "cluster2-mgmt.example.com"

$cred = Get-Credential -UserName "capacity-report" -Message "ONTAP read-only login"
$clusterList = Get-Content -Path "C:\Scripts\clusters.txt"
.\Get-NetAppVolumesOverThreshold.ps1 -Clusters $clusterList -Credential $cred -ThresholdPercent 75 -OutputPath "C:\Reports\volumes-over-threshold.csv"

Querying cluster1-mgmt.example.com ...
Querying cluster2-mgmt.example.com ...

Cluster                   Svm          Volume           Style    SizeGB UsedGB AvailGB PercentUsed NearlyFull Aggregate
-------                   ---          ------           -----    ------ ------ ------- ----------- ---------- ---------
cluster1-mgmt.example.com svm_prod01   vol_sql_logs     flexvol     512    492      20          96       True aggr1_n1
cluster1-mgmt.example.com svm_prod01   vol_app_data     flexvol    2048   1782     266          87      False aggr1_n2
cluster2-mgmt.example.com svm_files02  vol_home_shares  flexgroup  4096   3379     717          82      False aggr1_n1,aggr1_n2

3 volume(s) at or above 80% used across 2 cluster(s).
Results written to C:\Reports\volumes-over-threshold.csv

Invoke-RestMethod -Uri "https://cluster1-mgmt.example.com/api/storage/volumes?state=online&space.percent_used=%3E%3D80&fields=name,svm.name,space.percent_used" -Authentication Basic -Credential $cred |
    Select-Object -ExpandProperty records |
    Select-Object -Property name, @{ Name = 'svm'; Expression = { $_.svm.name } }, @{ Name = 'percent_used'; Expression = { $_.space.percent_used } }

<#
.SYNOPSIS
    Reports every volume across a set of NetApp ONTAP clusters above a capacity threshold.
.DESCRIPTION
    Calls GET /api/storage/volumes on each cluster through the ONTAP REST API, asking the cluster to
    return only online volumes whose space.percent_used is at or above the threshold, with just the
    fields the report needs. Follows _links.next for large result sets. Reports FlexVol and FlexGroup
    volumes (not FlexGroup constituents), flags volumes past their own nearly-full threshold, and
    applies the same bar to every cluster regardless of how each cluster's alerting is configured.
.PARAMETER Clusters
    Cluster management hostnames or IPs to sweep.
.PARAMETER Credential
    Credential used against every cluster. Prompts if omitted.
.PARAMETER ThresholdPercent
    Minimum space.percent_used to report a volume. Defaults to 80.
.PARAMETER SkipCertificateCheck
    Accepts self-signed cluster certificates. Use only on a management network you trust.
.PARAMETER OutputPath
    If set, writes the results to this CSV path in addition to the console.
.EXAMPLE
    .\Get-NetAppVolumesOverThreshold.ps1 -Clusters "cluster1-mgmt.example.com", "cluster2-mgmt.example.com" -ThresholdPercent 75
.NOTES
    Author  : Thomas Lasswell (https://www.techcolumnist.com)
    Version : 1.0 (2025-08-13)
    Requires: PowerShell 7, ONTAP 9.9 or later, a login with the http application and readonly role
#>
#Requires -Version 7.0
[CmdletBinding()]
param (
    [Parameter(Mandatory = $true)]
    [string[]]$Clusters,

    [Parameter(Mandatory = $false)]
    [System.Management.Automation.PSCredential]$Credential,

    [Parameter(Mandatory = $false)]
    [ValidateRange(1, 100)]
    [int]$ThresholdPercent = 80,

    [Parameter(Mandatory = $false)]
    [switch]$SkipCertificateCheck,

    [Parameter(Mandatory = $false)]
    [string]$OutputPath
)

if (-not $Credential) {
    $Credential = Get-Credential -Message "ONTAP read-only login used for every cluster"
}

$fields = @(
    'name', 'svm.name', 'state', 'style', 'aggregates.name',
    'space.size', 'space.used', 'space.available', 'space.percent_used',
    'space.snapshot.reserve_percent', 'space.nearly_full_threshold_percent'
) -join ','

$restParams = @{
    Method         = 'Get'
    Authentication = 'Basic'
    Credential     = $Credential
    ErrorAction    = 'Stop'
}
if ($SkipCertificateCheck) {
    $restParams['SkipCertificateCheck'] = $true
}

$results = foreach ($cluster in $Clusters) {
    Write-Host "Querying $cluster ..."

    # Filter on the cluster: online volumes at or above the threshold. ">=" is URL-encoded.
    $nextPath = "/api/storage/volumes?state=online&space.percent_used=%3E%3D$ThresholdPercent&max_records=500&fields=$fields"

    while ($nextPath) {
        try {
            $response = Invoke-RestMethod -Uri "https://$cluster$nextPath" @restParams
        } catch {
            Write-Warning "Could not query ${cluster}: $($_.Exception.Message)"
            break
        }

        foreach ($volume in $response.records) {
            $space = $volume.space
            $nearlyFullAt = if ($space.nearly_full_threshold_percent) { $space.nearly_full_threshold_percent } else { 95 }

            [PSCustomObject]@{
                Cluster        = $cluster
                Svm            = $volume.svm.name
                Volume         = $volume.name
                Style          = $volume.style
                SizeGB         = [math]::Round($space.size / 1GB, 0)
                UsedGB         = [math]::Round($space.used / 1GB, 0)
                AvailGB        = [math]::Round($space.available / 1GB, 0)
                PercentUsed    = $space.percent_used
                NearlyFull     = $space.percent_used -ge $nearlyFullAt
                SnapReservePct = $space.snapshot.reserve_percent
                Aggregate      = ($volume.aggregates.name | Sort-Object -Unique) -join ','
            }
        }

        # ONTAP returns a relative next link while more records remain.
        $nextPath = $response._links.next.href
    }
}

$results = @($results | Sort-Object -Property PercentUsed -Descending)

$results | Format-Table -Property Cluster, Svm, Volume, Style, SizeGB, UsedGB, AvailGB, PercentUsed, NearlyFull, Aggregate -AutoSize

Write-Host ""
Write-Host "$($results.Count) volume(s) at or above $ThresholdPercent% used across $($Clusters.Count) cluster(s)."

if ($OutputPath) {
    $results | Export-Csv -Path $OutputPath -NoTypeInformation -Encoding UTF8
    Write-Host "Results written to $OutputPath"
}