In many situations, it is necessary to track the usage of datastore usage in our environment because if your datastore is full , it will cause a potential outage to your virtual machines in your environment. It is really in need of maintaining some threshold of free storage % always to avoid potential issues. This simple powershell script will helps you pull the usage and % of free space report of all the datastores in your vCenter server.

Enter your vCenter Server Name  and Specify the output file name as per your wish. Both items are marked in yellow in the below script.

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Connect-VIServer vCENTER_SERVERNAME
Function Percentcal {
    param(
    [parameter(Mandatory = $true)]
    [int]$InputNum1,
    [parameter(Mandatory = $true)]
    [int]$InputNum2)
    $InputNum1 / $InputNum2*100
}

$datastores = Get-Datastore | Sort Name
ForEach ($ds in $datastores)
{
    if (($ds.Name -match “Shared”) -or ($ds.Name -match “”))
    {
        $PercentFree = Percentcal $ds.FreeSpaceMB $ds.CapacityMB
        $PercentFree = “{0:N2}” -f $PercentFree
        $ds | Add-Member -type NoteProperty -name PercentFree -value $PercentFree
    }
}
$datastores | Select Name,@{N=”UsedSpaceGB”;E={[Math]::Round(($_.ExtensionData.Summary.Capacity – $_.ExtensionData.Summary.FreeSpace)/1GB,0)}},@{N=”TotalSpaceGB”;E={[Math]::Round(($_.ExtensionData.Summary.Capacity)/1GB,0)}} ,PercentFree | Export-Csv c:\datastorereport.csv -NoTypeInformation

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Output of the above script will be similar to the below table. It will provide the Datastore name, UsedSpace in GB , TotalSpace in GB and % of free space on the datastore.

Name	UsedSpaceGB	TotalSpaceGB	PercentFree
Prod_Datastore_T1_001	674	676	0.42
Prod_Datastore_T1_002	253	256	1.24
Prod_Datastore_T2_001	491	500	1.7
Prod_Datastore_T2_002	359	367	2.07
Dev_Datastore_001	250	256	2.18
Lab_Datastore_001	661	676	2.24
ISO_Datastore_001	2342	2397	2.28