Preferred Servers in provisioning does not work as it does with Software Distribution and Patch/Compliance. There is a third party application developed, I believe, by a LANDesk employee located << here. >> I am not clear on how it works so I do not use it in provisioning.
The following information assumes you already have your preferred servers setup and they contain the image and are maintained with either Content Replication or as we use Robocopy. This is what we do at my company to handle deployments on the East Coast, West Coast, and North East.
Each OS Image Template I create contains a template variable called SERVERSHARE. SERVERSHARE=UNC of Preferred Server and Image Location:
So for every map drive action instead of inserting the UNC of the share I now just use the SERVERSHARE template variable. Once I have a master template I can copy it, rename it, and change the Replacement Value for the SERVERSHARE variable to whatever preferred server I choose. Most software installed is an execute file action, as when we set this up the distribute software action was unreliable.
There have been some software titles that I could only get to work with a distribute software action but have since found out that this action uses SDCLIENT.exe and will figure out what preferred server to go to. Personally I find execute file to be a lot more reliable, fast, and easy. Just map the drive with this new variable and let it rip. Everything runs from source rather then taking the time to download, unzip if necesssary, and install on the client.
In the screenshot below you will see the Map Drive action using the %SERVERSHARE% Template Variable. The variables used for credentials are Public Variables created by clicking the button on the OS Deployment Toolbar.
If you do not yet have preferred servers setup they are real easy to do. Just mirror your software library and patch library shares on each preferred server. The LDMS 9.0 User Guide can easily walk you through it found << here. >> Pages 147-149 to setup the file/web share. Page 70 contains the instructions on configuring preferred server credentials. Pages 156-158 shows you how to set them up in the console, a little outdated for SP2 but same basic concept, and also gets into a little more details of how they work. Hope this helps!
Ascott tat is a very good explanation - good stuff. I echo the use of exe over sdclient on software distribution, significantly faster - for now. Here are some other posts on preferred server.