4 Replies Latest reply on Nov 4, 2008 11:03 AM by bfrank

    Monitoring ESX 3.5

      So yesterday I watched a webcast where Josh Stephens was talking about the new free tool to monitor VMware.  He said it was possible to monitor VMware using Orion so I used his posting in the blog to add our SNMP settings and they connected right up to Orion no problem.  Here is my question.  Now that it is set we are getting a very wierd stat and I don't understand it.

       All of our servers are registering 90%+ on what they are calling "Real Memory"  I'm not sure what that is...  Can someone explain to me what that is representing?  These servers have 16 GB of RAM and should not be 90% or more used.


        • Re: Monitoring ESX 3.5


          Where are you seeing these numbers?  In Orion?  The memory utilization reported from the ESX server via the VMware Infrastructure Client contains more information that what the free tool and Orion show.

          New in Orion 9.1 is the ESX Details page that shows the details gathered from an individual ESX server.  There it reports the allocated amount of memory to each VM and the total amount of CPU and memory being used by each VM.

          A brief explanation of memory in VMs:

          ESX server allows to you tell how much memory a VM is allowed to use each time you set up a VM. For our example we'll use 1 GB.  When that VM is running the ESX server will allocate an amount of the physical RAM to that VM, usually something less than the maximum allowed.  Let's say 512 MB for our example.  Next, the VM actually uses some of that allocated amount, as reported by the ESX server.  For our example, we'll say 256 MB. Now because of the magic of virtualization, the host OS on that VM may believe that it is using an amount of RAM different than what the ESX server is allowing it to use.  So let's say our OS thinks it is using 300MB.

          So for our example.  Orion reports the 1 GB and 256 MB on the ESX Details Page, and 300 MB on the VMs Node Details Page.

          The VMware IC will report the 1 GB, 512 MB and 256 MB values.

          Our free tool reports the 1 GB and 256 MB values.

          I am not sure what the "Real Memory" value is indicating, but often then amount of memory that the ESX server has *allocated* for all the VMs running on it will be the biggest number of the memory reported.  This value is only visible on the IC and gives you an idea of what how many more VMs you may be able to run on that ESX server.

          I know I haven't really answered your question, but hopefully have given you a little insight to what the numbers mean.  If you can let me know what OIDs you're polling, or if you're using 9.1 which screen you are seeing the numbers, then maybe I can shed more light.


            • Re: Monitoring ESX 3.5

              Hopefully this will answer your questions...


                • Re: Monitoring ESX 3.5

                  Picture worth 1000 words.

                  So if I am interpreting your correctly, this is from your ESX server.  This volume reporting is a little different in Linux and VMware and is in no way accurately reporting your actual RAM size (obviously).  This Real Memory Calculation (RAM) is based off of what the ESX kernel is using.  It is very efficient at allocating its memory and will almost always use nearly all of it, thus leaving more for the VMs.  So this number is nothing to worry about.

                  The other memory gauges and charts in Orion 9.1 give a much more accurate vision of actual memory usuage of the entire server.

                  Please let me know if I can clarify any further.

              • Re: Monitoring ESX 3.5

                Thanks a million.  I removed that object from each of the ESX servers so we don't have to look at the high level warning.  Thanks!