Citrix XenServer virtual server technologies provide companies with the ability to do more with less resources. While this technology makes computing easier and efficient, virtualization makes IT infrastructures harder to monitor and manage. Effective monitoring and management is critical for these environments to be adequate replacements for traditional hardware-based infrastructures.

The eG Monitor for XenServer Infrastructures (the eG VM Monitor^TM), part of the eG Enterprise Suite, is a comprehensive solution for monitoring and managing all aspects of virtual hosts and guests, whether the infrastructure is used to support server or desktop applications. Coupled with the ability of the eG Enterprise Suite to monitor over 80 applications, including Citrix, Microsoft, Oracle, IBM, SAP, and others, the eG VM Monitor – with its patent-pending In-N-Out Monitoring^TM technology -- provides a comprehensive end-to-end solution for monitoring and managing the performance of virtual IT infrastructures.

Administrators can use the eG VM Monitor to monitor the performance of their physical and virtual infrastructures, troubleshoot problems to determine where the root-cause lies, assess where capacity bottlenecks are, and plan the usage of their servers and applications to optimize the utilization of the physical and virtual resources. The key customer benefits of this solution include higher uptime, better end-to-end performance, and operational cost savings through more effective utilization of key IT staff.

Multi-tier IT infrastructures are a nightmare to troubleshoot because of the dependencies that exist between application tiers. For instance, a failure in the database tier could result in slow downs in the application and web server tiers. Hence, monitoring solutions that view the infrastructure as independent silos cannot effectively monitor and diagnose problems in such infrastructures. The addition of virtualization to such infrastructures makes monitoring and management of these infrastructures even more challenging!

Fig 1: A problem in one application can affect all the other applications involved in the service delivery.

Fig 2: Excessive disk reads by the media server slow down Oracle database accesses

While knowing which VM is consuming excessive resources is helpful, it is even more important to understand whether the VM's behavior is normal. For instance, a memory leak in one of the applications executing inside a VM may be causing the VM's memory usage to increase over time. In such cases, it is essential that the monitoring solution be able to look in-depth into each guest VM and detect abnormalities. While deploying individual agents inside each VM provides this level of visibility, this can result in additional resource overhead, licensing fees, and maintenance cost.

Performance degradations in a virtual infrastructure may also be because a virtual machine has not been configured with sufficient resources to handle its workload. A monitoring solution must be able to differentiate problems resulting from inadequate virtual machine configuration and those resulting from hot-spots created by uneven distribution of load across ESX/ESXi servers.

The eG VM Monitor extends the eG Enterprise monitoring technology to virtual environments. Using a patent-pending In-N-Out Monitoring^TM approach, the eG VM Monitor provides a comprehensive view of an ESX/ESXi Server, including the performance of the VM kernel, the service console and all of its virtual machines. Agent-based monitoring can be used for ESX 3 or 3.5 servers, while agentless monitoring can be used for ESXi servers. When agent-based monitoring is used, eG agents only have to be installed on the ESX server -- not on individual guests. Using ESX server APIs, the agents provide an “outside view” of a guest VM’s performance. The relative resource usage levels of the guest VMs show where the performance hogs exist. To complement the outside view, the eG agent obtains an “inside view” that details the user activity, resource allocation and the application mix running inside the VM guest operating system. All the capabilities of agent-based monitoring are also available with the agentless monitoring option for Citrix XenServers. The eG VM Monitor automatically baselines all the metrics it collects, so that IT administrators can be informed proactively of any deviations from the norm. No other virtualization monitoring solution offers this combination of features.

Monitoring VM guests: eG agents track the performance of each guest VM relative to shared infrastructure resources (outside view) as well as the workload and application mix of the individual guest VMs (inside view).

From a monitoring and management standpoint, the eG monitor for XenServer infrastructures goes well beyond managing virtualized servers as discrete entities. End-to-end business service views show the applications and network devices that support each business service, and the inter-dependencies among them. Applications are associated with the virtual machines they run on, and each virtual machine is mapped to the physical machine upon which it is hosted.

The dependency of the virtual machines to physical machines is determined dynamically, so as to support the XenMotion^® Live Migration technology. A patented root-cause diagnosis engine analyzes the service topology graphs and the virtual-to-physical machine mappings to pin-point where the problems areas in the infrastructure lie.