Preferred Distribution Points

One of the great features in ConfigMgr 2012 is the ability to use preferred distribution points to allow clients to request content from a preferred locations. I have had some feedback from customers that this feature either doesn’t work or is not very well documented.

Boundary Groups

First of all, quick discussion on boundary groups. Preferred distribution points work on the back of boundary groups where we can add content servers (distribution points) to a particular boundary group. This means that clients which report in on a specific boundary within a boundary group will have that distribution point as a preferred one.

When the client requests content, the management point sends a list of preferred distribution points for that specific client which has the content. When more than one distribution point is provided the following logic is used to pick which distribution point should be used first.

  1. Network boundaries
  2. Forest trust
  3. HTTP Locations (HTTPS are ordered higher up)
  4. SMB locations

If multiple distribution points fall within a single category then one is picked at random.

Setting Application Properties

In a specific application we can tick a box which sets a flag on the properties to say if this content is not on a clients preferred distribution point then distribute the content to it.

You can see this option ticked and highlighted in the box below.

pref_1

We then distribute the content to some other distribution points, in this example below you can see I have distributed it to ROLES01 and CLOUDDP.

pref_2

When you first request the application you will get an error, the error isn’t great if we are honest it doesn’t tell you the content is not available. What would be better in this instance is the status changing to “Waiting for content…”. Instead we need to wait until the application is attempted again at a later point (I believe this is about 60 minutes).

pref_3

If we look at the above extract from CAS.log when we perform this request. The first yellow highlighted line says that 0 distribution points have been discovered with the content available. A little over a minute later the second yellow line says we now have one distribution point with the content. The lines outlined in red then show us that the content is getting downloaded from our download location CM01 which is our third distribution point.

Content Fallback

If you have fallback enabled for content location then the following rules will apply in order to pick a fallback distribution point.

  1. Forest trust
  2. HTTP(S) locations
  3. SMB locations

When on-demand distribution is configured, depending on the settings that you configure, the client might not go to a fallback distribution point, but instead the content might be downloaded to the preferred distribution point.

There you have it. I hope this clears up any confusion that you might have with this specific feature.

Advertisements

Tags: , , , , ,

About Martyn

Martyn is one of the Senior Cloud Architects and DevOps Team Leader at one of the worlds leading Cloud Transformation Specialists Inframon. Martyn is responsible for the architecture of some of the largest Azure deployments in EMEA and is a advisor to a many businesses on their strategies. Martyn is a regular speaker at Microsoft events and community events on Azure and DevOps, giving his insight to a growing number of audiences.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: