This is not really news – more so a reminder for myself that might also help someone else.

We’ve been aware of using default values in various areas of SCOM, especially in command channel and notification workflows. I’ve found this helpful in the past, but where I’ve used default values most often is in variable notation elements when developing management packs. It’s especially useful when using modules such as the System.OleDbProbe modules, because often times when we query a database in a workflow the results may be empty; there are some reliable and consistent data returned using this module, but if no records are returned then we need might need to use a default variable if further processing is required, like in a script write action.

Here is an example of using a default value in a recovery, which is helpful if no records are returned by a query probe in a diagnostic.

<Value>$Data/[Default='']/Diagnostic/DataItem/RowLength$</Value>

Also, a little tip for getting all data if a simulation isn’t possible and you’re working blindly, as is the case when developing diagnostic and recovery tasks; you can dump the entire data stream into the recovery output by simply using <Value>$Data$</Value>.

Now you can reference something like this article to figure out the value xpath.