Get Percent Free Space

I’ve put together a function that will return the percentage free space on a given logical drive for a specified server. The function in the following script is really doing all the hard work. The rest of the script is simply a demonstration on how to call the function. The script uses WMI and queries the Win32_LogicalDisk for the size and freespace properties. With these values it’s pretty simple to calculate a percentage.

‘GetPercentFreeDrive.vbs

‘specify alternate credentials for remote systems
strUsername=”"
strPassword=”"

strSrv=InputBox(“What computer do you want to query”,”Get Percent Free”,”localhost”)

strDeviceID=InputBox(“What drive do you want to query?”,”Get Percent Free”,”c:”)

WScript.Echo UCase(strDeviceID) & ” on ” & UCase(strSrv) & ” has ” & GetPercent(strSrv,strDeviceID,strUsername,strPassword) & ” free space.”

Function GetPercent(strSrv,strDeviceID,strUsername,strPassword)
‘deviceID is the drive letter and colon, eg E: with no trailing \

On Error Resume Next
Dim SWBemlocator,objWMI,objRef
Const wbemFlagReturnImmediately=&h10
Const wbemFlagForwardOnly=&h20

strQuery=”Select DeviceID,Size,FreeSpace from Win32_LogicalDisk WHERE DeviceID=’” & strDeviceID & “‘”

‘strip out any trailing \ if found
If Right(strDeviceID,1)=”\” Then strDeviceID=Replace(strDeviceID,”\”,”")

‘validate strDeviceID
If Len(strDeviceID)=2 And Right(strDeviceID,1)=”:” Then

Set SWBemlocator = CreateObject(“WbemScripting.SWbemLocator”)
SWBemlocator.Security_.ImpersonationLevel=3
SWBemlocator.Security_.AuthenticationLevel=WbemAuthenticationLevelPktPrivacy
Set objWMI=SWBemlocator.ConnectServer(strSrv,”\root\CIMV2″,strUsername,strPassword)

Set objRef=objWMI.ExecQuery(strQuery,”WQL”,wbemForwardOnly+wbemFlagReturnImmediately)

For Each dev In objRef
iFreeSpace=dev.FreeSpace
iSize=dev.Size
Next

If iSize=”" Then
GetPercent=”Drive Not Found”
Else
GetPercent=FormatPercent(iFreeSpace/iSize,2)
End If