Virtual Servers and Applications Performance Management

One of the hottest trends in the management of servers these days is to virtualize them using either VMware or Microsoft Virtual Server. Replacing lightly used physical servers with virtual ones has many benefits including:

• Many small dual processor servers can be consolidated into one server with more CPU’s. This reduces complexity, saves money on networking, power, etc., while also collapsing several underused resources into one appropriately used resource
• Virtual servers can be more easily provisioned than can a new physical server
  In some cases (VMware, VMotion, and a SAN) you can even move live virtual servers from one machine to the next
• If you are paying someone (either an outsourcer or your IT department via chargeback) a per server fee to manage your servers, you can save quite a bit of money by moving from N smaller servers to fewer large servers.

However, moving to an environment of virtual servers brings with it a new set of challenges:

• As is always the case with new and innovative platforms, the vendor of the platform (Microsoft, Sun, or in this case EMC/VMware) does not provide all of the management tools that you need to effectively use the platform in production.
• The vendors of management tools typically lag behind the platform vendors in terms of full support for the platform (Citrix got to be a $750M company, and support for Citrix among the management vendors stills lags behind the support for J2EE and Windows/COM+/.Net.
• The per server licensing models used by most management vendors do not work in the virtual server environment. If an enterprise puts 10 VM’s onto a four CPU server, that enterprise is going to be loath to pay $2000 in licensing fees for each VM, in place of the previous charge of $2000 or $4,000 for the license for one physical four CPU server.
• There are no systems management or APM products available today that are structured to deal with properly monitoring resources across both the host OS (in the case of VMware ESX, a flavor of Unix), and several guest OS’s each of which (again the case of VMware) might be different from each other. For example of two processes running in two different VM’s contend for a resource in the host OS, and each experience high context switches as a result, there is no way to find out that it is those two processes and what the resource in contention is.
• There are no tools for basic capacity planning. There is simply no good way to know how many virtual servers of a given type will fit onto a physical server of a given type. So, you cannot calculate the economic benefits of a consolidation project before attempting to implement at least a part of that project.

In summary, while virtualization of servers is a hot trend in IT right now, this trend cannot continue to make inroads into core production systems unless a set of APM vendors emerges that allows the IT staff to ensure the service level of the applications on the virtual servers. Since the APM industry is still struggling to deal with everything except custom developed J2EE applications (for which there are a number of effective solutions), it will likely be a while before this need is met. However, it would not be surprising to see a nimble APM startup jump on this opportunity, as a way to start gaining traction in that difficult to penetrate market for IT management solutions.

Bernd Harzog
CEO
Applications Performance Management Experts
www.apmexperts.com
bernd.harzog@apmexperts.com