The Inside View of VMs Layer

The Outside View of VMs layer provides an “external” view of the different VM guests - the metrics reported at this layer are based on what the XenServer host is seeing about the performance of the individual guests. However, an external view of the VM guest operating system and its applications may not be sufficient. For instance, suppose one of the disk partitions of the guest operating system has reached capacity. This information cannot be gleaned from host operating system. Likewise, bottlenecks such as a longer process run queue or a higher disk queue length are more visible using an internal monitor. Internal monitoring (from within the guest operating system) also provides details about the resource utilization of different application(s) or processes.

The tests mapped to the Inside View of VMs layer provide an "internal" view of the workings of each of the guests - these tests execute on an XenServer server host, but send probes into each of the guest operating systems to analyze how well each guest utilizes the resources that are allocated to it, and how well it handles network traffic and loading.

By default however, clicking on the Inside View of VMs layer, does not display the list of tests associated with that layer. Instead, Figure 1 appears, which provides you with an overview of individual guest performance.


Figure 1 : A list of guest operating systems on an XenServer host and their current state

To return to the layer model of the Citrix XenServer and view the tests associated with the Inside View of VMs layer, click on the component layers link in Figure 1. You can now view the list of tests mapped to the Inside View of VMs layer, as depicted by Figure 2 below.

Figure 2 : The tests associated with the Virtual Servers layer

As indicated in Figure 2, the tests associated with this layer monitor different aspects of each virtual guest. Disk space utilization, disk activity levels, CPU utilization, memory usage levels, network traffic, etc. are all monitored and reported for each virtual guest hosted on the XenServer. Detailed diagnosis for these tests provide details of individual processes and their utilization levels.

The tests associated with this layer are described in detail below.