Delete differential images based on available free space

Applies to: Standard, Professional and Server Editions of Macrium Reflect only.



The instructions presented in this topic demonstrate how you would use VBScript to delete the oldest differential images in a backup set based on the amount free space available on the backup drive.

In the following example we generate a VBScript source file that, if necessary, creates 5 GB of free space on the target drive by deleting the oldest differential images before running the current differential.

Caution Only run this script on a differential backup set. Running the script on incremental backup sets leads to loss of backup integrity.


To delete differential images based on available free space

  1. In the Backup Definition Files tab, right-click a backup definition file and choose Generate a VB Script File from the shortcut menu.

    The VBScript generation dialog box appears.

  2. Leave the options as defaults but change the file name for clarity.

  3. Select the VBScript Files tab, right-click the new file and select Edit from the shortcut menu.

    The VBScript file opens in the system default text editor, generally this is Notepad.

  4. For clarity, switch off word wrap. In notepad, choose Edit > Word Wrap.


  5. Edit the file in Notepad as follows:

    Before the line:

    ' Do the backup

    Copy and paste the following:

    ' Create 5GB free space
    CreateSpace "N:\Backups", 5 * 1024

    Note The number 5 represents the number of GB of free space you want to create to ensure you have enough space before running the backup. Change 'N:\Backups' to the path of your image.


  6.  At the end of the file copy and paste the following code:

    Function CreateSpace(ByVal drvPath, MB)
    While GetFreeSpaceMB(drvPath) < MB
    If DeleteOldestFile(drvPath) = false Then
        Exit Function
    End If
    End Function

    Function GetFreeSpaceMB(ByVal drvPath)
    Dim objFSo, d
    Set objFSo  = CreateObject("Scripting.FileSystemObject")
    If Not objFSO.FolderExists(drvPath) Then
    ' return a big number if the folder doesn't exist
    GetFreeSpaceMB = 1000 * 1024 * 1024
    Exit Function
    End If
    Set d = objFSo.GetDrive(objFSo.GetDriveName(drvPath))
    GetFreeSpaceMB = d.FreeSpace/ (1024 * 1024)
    End Function

    Function DeleteOldestFile(ByVal drvPath)
    Dim objFSo, colFiles , dtmOldestDate, strOldestFile, objFolder, objFile  
    Set objFSo = CreateObject("Scripting.FileSystemObject")
    Set objFolder = objFSO.GetFolder(drvPath)
    Set colFiles = objFolder.Files
    dtmOldestDate = Now

    For Each objFile in colFiles
    If objFile.DateLastModified < dtmOldestDate _
    AND Left(Right(objFile.Path, 11), 2) <> "00" _
    AND Right(objFile.Path, 6) = ".mrimg" Then
        dtmOldestDate = objFile.DateCreated
        strOldestFile = objFile.Path
    End If

    If strOldestFile <> ""  Then
    objFSO.DeleteFile strOldestFile
    DeleteOldestFile = true
    DeleteOldestFile = false
    End If
    End Function

  7. Save the file.

  8. Execute or schedule the VBScript source file in exactly the same way as a backup definition file. See Schedule backups.