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Re-Evaluating Disaster Recovery for Virtual Server Environments

September 23, 2008


There’s an old saying: “If you fail to plan, you plan to fail.” Those words could describe the challenge of meeting high availability and disaster recovery requirements in virtual server environments.


There’s an old saying: “If you fail to plan, you plan to fail.”
Those words could describe the challenge of meeting high availability and disaster recovery (HA/DR) requirements in virtual server environments. In part that’s because HA/DR isn’t a core competency of server virtualization vendors. Read on to learn what IT managers need to do to get the same level of HA/DR protection for mission-critical applications and data in the virtual world that they expect in the physical one.

Enterprise-class HA/DR

What are the HA/DR requirements for a mission-critical enterprise application? Let’s start with a definition.
“A mission-critical application is an application that needs to be running within eight hours or less of an incident that causes downtime,” observes Dan Lamorena, a Senior Product Marketing Manager at Symantec.
According to Lamorena, the first step in building an HA/DR solution is to monitor the status of the mission-critical application. That means monitoring the application as well as all of its dependencies, including the application components, the operating system, the physical server, the network connection, the storage connection, even the health of the data center itself.
The next step in an HA/DR solution is to take appropriate action once it has been determined that an application has failed. As Lamorena puts it: “If any of the components that are being monitored have a fault, the appropriate action is automatically taken – that is, the individuals responsible for the application are notified of the outage and the recovery process begins.”
In the physical world, IT organizations use high availability clustering software to monitor and restart the application, enabling end users to continue their normal operations as quickly as possible. Recent natural disasters, such as Hurricane Katrina, have underscored the need for HA/DR solutions that span multiple locations over great distances. In addition to automated application failover, organizations will need to continuously replicate data at the secondary site.
Regardless of whether a mission-critical application is running in a physical or virtual environment, stringent service-level expectations continue to apply. That said, the virtual environment does present IT teams with significant new challenges.

Virtualization ‘changes the game’

As the global results of Symantec’s fourth annual IT Disaster Recovery Survey clearly show, virtualization is driving an increasing number of organizations to re-evaluate their disaster recovery plans. The survey, released in August, found that virtualization is the major factor causing more than half of respondents globally (and 64% in North America) to re-evaluate those plans.
In the words of one of the authors of the survey, virtualization is “changing the game” for disaster recovery today by adding another layer of technology that needs to be managed and monitored. Virtualization is a new technology, and often the native tools that provide availability are immature and do not offer the level of protection that enterprises have come to expect. For example, these tools may lack basic availability features for monitoring the health of an application running in a virtual server.
In addition, the survey finds that applications and data in virtual environments “pose a difficult challenge since availability solutions for physical environments may not work in virtual environments.” In fact, respondents cited “different tools for physical and virtual environments” as the biggest challenge in protecting mission-critical data and applications within virtual environments.
As Symantec’s Lamorena has observed: “Building a new HA/DR infrastructure [for server virtualization technologies] may lead to a siloed work staff and greater operator inefficiencies as workers need to learn or create additional tools, log into more management consoles, and get their arms around a more complex IT environment.”

Enterprise-class HA/DR for virtual environments

When choosing an HA/DR solution for their virtual server environments, IT organizations need to ensure that the technology meets certain criteria, according to Lamorena. And if mission-critical applications are being placed in virtual servers, the solution must:
  • monitor the application and application resources, including the virtual machine, network components, storage components, and the physical server
  • notify administrators of failures to any of those resources
  • automate the recovery and start-up of applications, including reconnecting users to the restarted application
  • integrate disaster recovery practices, including replicating data and automating application startup at a distant second site.
Without these key components, mission-critical applications won’t be protected.
Symantec also recommends that organizations implement a holistic protection solution across virtual environments, remote offices, servers, applications, and databases that can quickly recover vital data and systems in the event of a disaster. In addition, consolidating on a single management tool that manages both physical and virtual environments will make it simpler to manage the increasing number of tools in their environment.


Today, as more mission-critical applications and data are deployed in a virtual environment, organizations must evaluate the most efficient ways to manage them in both physical and virtual environments. They must also incorporate a comprehensive, proven HA/DR plan into their overall business strategy. Ultimately, this will help ensure the successful recovery of applications and data with the least amount of impact to business operations should a disaster occur.

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