Kevin Holman's System Center Blog

Posts in this blog are provided "AS IS" with no warranties, and confers no rights. Use of included script samples are subject to the terms specified in the Terms of UseAre you interested in having a dedicated engineer that will be your Mic

OpsMgr: Logical Disk free space alerts don’t show percent and MB free values in the alert description – updated for Server 2012

OpsMgr: Logical Disk free space alerts don’t show percent and MB free values in the alert description – updated for Server 2012

  • Comments 11
  • Likes


I previously wrote about some updated Base OS Monitoring Packs that shipped, adding many new features and fixes for monitoring the OS, and some issues that the changes created.  You can read the old article here:

One of the areas this new MP focused on, was changing a lot of the “average threshold” monitors to “consecutive sample” monitors.  This helps control the noise when there are short term fluctuations in a performance value, or when some counters can spike tremendously for a very short time, skewing the average.  So for the most part – changing these over to consecutive samples is a good thing.  That said, one of the changes made was to the Logical Disk free space monitors, both for Windows Server 2003, 2008, and 2012 disks.

The script used to monitor logical disk free space in previous versions of the Monitoring Pack would output two additional propertybags for free space in MB and Percent.  This was very useful, because these values could easily be added to the alert description, alert context, and health explorer.  This was very beneficial, because the consumer of the alert in a notification knew precisely how much space was left for each and every alert generated.  Here are some examples of how it looked previously:




Now – when the new MP shipped – this script was changed to support the new consecutive samples monitortype, and was completely re-written.  When it was rewritten, the script no longer returned these propertybags, so they were removed from the alert description, alert context, and health explorer.  The current MP (6.0.6958.0) looks like this:


The monitor still works perfectly as designed, and you are alerted when thresholds that you set are breached.  The only negative side effect is the loss of information in the alert description.

Several customers have indicated that they preferred to have these values back in the alert description.  The only real way to handle this scenario, until the signed and sealed MP gets updated at some point in the future, is to disable the built in monitor, and enable a new monitor with an alert description that you like.

I have written three addendum MP’s attached at the bottom of this article, which do exactly that – I created new monitors (essentially the same monitors from the previous older version of the Base OS MP’s) and included overrides which disable the existing monitors from the sealed MP’s.  These new monitors are essentially exact copies of the monitors before they got updated.  They run once per hour and have all the default settings from the previous monitors.

With the addendum MP imported – health explorer looks like the following:


Note the new name for the addendum monitor, and the fact that the existing “Logical Disk Free Space” monitor is unloaded as it is disabled via override.

These addendum MP’s for Windows Server 2003, 2008, and 2012 each simply include a script datasource, monitortype, and monitor to use instead of the items in the current sealed Base OS MP’s.  These addendum MP’s are unsealed, so you have two options:

  1. Leave them unsealed, and use them as-is.  This allows you to be able to tweak the monitor names, alert descriptions, and any other settings further.
  2. Seal the MP’s with your own key (recommended) after making any adjustments that you desire.  This will be necessary in order to create overrides for existing groups in other MP’s should you desire to use those.

One caveat to understand– is that any overrides you have created on the existing Base OS free space monitors will have to be re-created here on these new ones.  There is no easy workaround for that.

Let me know if you have any issues using these addendum MP’s (which are provided as a sample only) and I will try to address them.

Credits – to Larry Mosley at Microsoft for doing most of the initial heavy lifting writing the workaround MP.

Another approach:  Daniele Grandini has authored a different solution to this issue.  What he has done, is to add diagnostics to the existing sealed Logical Disk Free space monitors, which will add the actual disk free space in MB and % to Health explorer, so console users can have this information in real time as they use alert/health explorer to troubleshoot a free space issue.  His solution will not be able to add these values to the alert description to be sent in an email notification/pager/ticket, but for those companies that use the console and health explorer, it is a more graceful solution in that you don’t have to re-engineer all your existing overrides, and you still get the benefit of having consecutive samples.  It is worth a look:

  • great work, Kevin. I am a big FAN of your SCOM work. Can't thank you enough.....

  • Can someone stop Microsoft from loosing functions in new MPs. Enhancements should NEVER reduce existing functions.

  • Hi Kevin,
    Yes I have used your addendum monitor and it was a great help from you. Thank you for that. However, I am little confused here...SCOM does have newer version of monitor (Aggregate monitor) which shows space value. This aggregate monitor got one with MB value and one with % value. And I remember you talking about it in one of your article. Curious to understand your thoughts on V2 of addendum monitor. May be I am missing something here?

  • Fahim - you aren't missing a thing!

    The new monitors will cover EITHER % free, OR MB free, or both, but separate alerts. There are some customers who wish to have a single monitor that requires both, and the ability to trigger a single alert when both conditions are met, AND to have a customized alert description at the same time. There really isn't any strong reason to run this addendum, unless you are a custom who standardized on the "old" monitor, and don't like what they did to reduce the value in the alert description of the current shipping monitor.

  • Kevin,
    Thanks for your quick reply. Yes you are right. Having it in one alert helps. I might as well do that... So in regards to importing the monitor, is there a new way of doing it with V2?
    Thanks again,

  • Hey Kevin,

    Thanks for the hard work again.

    Quick question though. I installed the three management packs and I saw where they disabled the original monitors but when I tested the monitor by filling up a drive I didn't get anything. Then I realized you said yours are set to run every hour as opposed to every 15 minutes like in the old monitor. Was there a reason for this? Are there any issues overriding yours so it runs every 15 minutes as well?

  • Aaron - the original monitor ran once an hour, so that's what I set mine to. When it was changed to a consecutive samples monitor, they changed it to every 15 minutes, and 4 samples, so it had the EXACT same effect, it took an hour in a bad condition to detect. So you see very little difference.

    The only reason it isn't set more often by default, is due to the fact we don't like to run script based datasources too often, as scripts are more resource intensive than simple perfmon based datasources. However, you can run the monitoring script every 15 minutes if you want faster detection.

  • This does not seem to work for 2012 R2?

  • @Martin -
    What part doesn't work?

  • i don't seem to get any alerts for 2008 R2 and 2012 R2.

  • Maybe i have not set the override properly, i wan't alerts at 10% 10GB / 5% 5 GB which works for all other OS's.
    Otherwise a great mp, use it a lot for our hosting :)

Your comment has been posted.   Close
Thank you, your comment requires moderation so it may take a while to appear.   Close
Leave a Comment
Search Blogs