VisualBasic - Copy cache?

[LWA]

Hey all,
We are using the following script to performance monitor some SharePoint servers:

Option Explicit
Dim oFSO, oWN
Set oFSO = CreateObject("Scripting.FileSystemObject")
Set oWN = CreateObject("WScript.Network")

'// This makes sure the drive is not there
If Not oFSO.DriveExists("Z:") Then
'// Map the drive
oWN.MapNetworkDrive "Z:", "\\servername\GAS\uk\it_pub"
Else

End If

Dim olddate, nowdate

olddate = Now
'// Copying the file to the folder this script is stored in
oFSO.CopyFile "z:\downloadtest\test2.pdf", Replace(WScript.ScriptFullName,WScript.ScriptName,""), true
nowdate = Now
Msgbox "Time taken to copy the 10MB file was " & DateDiff("s", olddate, nowdate) & " seconds"

oFSO.deleteFile Replace(WScript.ScriptFullName,WScript.ScriptName,"") & "\test2.pdf"

'// Clean up
oWN.RemoveNetworkDrive "Z:"
Set oWN = Nothing
Set oFSO = Nothing 
Set olddate = Nothing
Set nowdate = Nothing

The first run of this code returns around 300seconds (which is what I'd expect) but the second run completes in about 6 seconds! Now I assume it is caching somewhere but does anyone know how to turn this off?

Thanks,
Leon

[scaryjim]

You expect it to take 5 minutes to copy a 10MB file across a network? Exactly what kind of network are you testing this on?

[yamangman]

Is it SCS?

[TLO]

Problem is that the FileSystemObject is going to be using Window's file copy mechanism and therefore caching is going to be used.

One method would be to vary the source file used - not sure if renaming or copying the file would be enough to trip up the caching - or to use an alternate method of copying the file. You can always read the source file and write to the remote destination within VB, not really the ideal way to do this but if VB is all you have available...

[mikerr]

Open it with the no buffering flag:

Public Const FILE_FLAG_NO_BUFFERING As Integer = &H20000000