Meet the needs of high availability and disaster recovery in virtual machine environments

Currently, many IT managers are considering migrating application software to a virtual machine environment. As we all know, with the application of virtualization technology, IT companies have benefited a lot from it, such as improving server utilization and accelerating server configuration. However, at the same time, enterprise users have also found that the risk of application software failure is also increasing.

High availability products from server virtualization vendors have many limitations, because high availability is not the core advantage of these companies. Therefore, users often turn to external vendors to obtain enterprise-level high availability and disaster recovery (HA/DR) requirements, especially for data center application software.

How can IT managers achieve the same high availability and disaster recovery protection in a virtualized environment as they do in a physical server? And what are the high availability and disaster recovery (HA/DR) requirements for mission-critical enterprise applications?

Enterprise-level high availability and disaster recovery (HA/DR) mission-critical applications are applications that need to run continuously for less than 8 hours and are not prone to failure. The first step in creating a high availability and disaster recovery (HA/DR) solution is to monitor the status of mission-critical applications. Is the application running normally? If not, the administrator must be aware of it immediately. In a physical environment, this means monitoring not only the application software, but all application-related components such as the application components, operating system, physical server, network connection, storage system and the health of the entire data center are monitored.

In addition to monitoring the application software and its components, the key step of the high availability and disaster recovery (HA/DR) solution is that the administrator can respond quickly and take measures once the application finds a problem. If any component under monitoring fails, feedback can be automatically given. In the physical environment, IT companies use high availability clustering software to monitor and restart applications so that the end user's software can resume normal operation as quickly as possible. If a regional disaster affects the entire data center, the company can apply a high availability and disaster recovery (HA/DR) solution to ensure that data is continuously backed up at the secondary address, and use clustering software to automatically implement the startup process of the application software at the backup address, so that users can continue to use these new application software instances.

Whether the application software is running in a physical environment or a virtualized environment, the service requirements of enterprise application software are the same. However, IT development teams will face many new challenges in meeting these business needs.

Challenges in a virtual machine environment

If an enterprise wants to benefit from server consolidation, it must carefully consider the risks it may face. One reason is that there are more applications running on fewer physical servers. In a physical environment, a physical server crash may only affect the applications running on this server. In a virtualized environment, a server may run 10 or 20 applications. Once a physical server running server virtualization technology fails, the impact will be much greater than in a purely physical configuration.

Another reason for the increased risk is the addition of a layer of technology that needs to be managed and monitored. In addition to the system components that IT administrators still need to manage and monitor in the physical environment, IT practitioners must now manage and monitor virtual servers and virtual infrastructure. The management and disaster recovery solutions for virtual infrastructure are different from those for physical environments. Disaster recovery tools used for physical servers may not be applicable to virtual servers, and the functionality and management interfaces may be different. As a result, server virtualization technology has become a platform that needs to be managed separately for IT development teams, which means that special high availability and disaster recovery (HA/DR) solutions need to be created for it. Creating a new high availability and disaster recovery (HA/DR) solution will increase the cost of hardware and software, and will also lead to a surge in personnel costs and inefficient operations processes because developers need to learn how to create additional tools, log in to more management consoles, and become familiar with more complex IT environments. [page]

Virtual machine high availability and disaster recovery (HA/DR) products

Currently, first-tier server virtualization vendors have launched a variety of products and claim to provide users with solutions that meet basic high availability and disaster recovery (HA/DR) needs. These server high availability and disaster recovery (HA/DR) solutions integrate many features, are relatively inexpensive and easy to use. A typical feature is that once a physical server fails, the virtual machine will be restarted on another physical server.

However, none of these solutions provide visibility and monitoring capabilities for applications, application components, virtual machines, network connections, storage systems, and the status of the data center itself. For some applications, this level of protection may be sufficient. But for mission-critical applications, most IT organizations require a higher level of protection and seek other solutions.

Many users consider live VM migration tools a key component of high availability plans because they keep VMs in working order while they are being migrated between servers. However, these solutions do not have application monitoring capabilities and require both servers to remain operational while the VMs are being migrated. These types of tools work well for planned maintenance, and they do not account for unexpected server crashes. Therefore, they are effective in preventing predictable crashes in virtualized environments, but have many limitations as high availability and disaster recovery (HA/DR) solutions.

If a server fails, the company will need to initiate a disaster recovery strategy to help the active data center migrate to a secondary data center. For most companies in a virtualized environment, this may be a manual process. Although data can be continuously replicated on the secondary address, this process cannot monitor the health of the address or achieve automated disaster recovery of the secondary address. Therefore, disaster recovery solutions for virtualized environments require a lot of manual work and expertise that are not used in actual disasters.

Enterprise-class high availability and disaster recovery (HA/DR) solutions for virtual machine environments

When choosing the right high availability and disaster recovery (HA/DR) solution for a virtual machine environment, IT organizations should first ensure that the technology they implement meets established standards. Most importantly, if companies intend to use mission-critical applications on virtual machines, they must ensure that they use an enterprise-class high availability and disaster recovery (HA/DR) solution that is:

Monitor applications and application resources, including virtual machines, network components, storage systems, and physical servers

Administrators can be notified promptly of any system failures

Automatic disaster recovery and restart of applications, including reconnecting users to restarted applications

Without these key solution components, users' mission-critical applications cannot be adequately protected.

Next, organizations should consider whether they need solutions for both local and remote high availability and disaster recovery plans. Should organizations have different plans, procedures, and infrastructure for disaster recovery? A suitable high availability and disaster recovery (HA/DR) solution for a virtual machine environment should work well with existing disaster recovery infrastructure, servers, and storage platforms. The testing process of an organization's disaster recovery plan is a key step to ensure its smooth operation. Testing a disaster recovery plan should be easy to perform without affecting the system environment. The testing process should be automated, independent, and controllable.

If the goal is to simplify the IT environment, IT organizations should prioritize HA/DR solutions to support both physical and virtual environments, which will also improve administrator efficiency. An ideal HA/DR solution should provide the same functionality and a single management interface for the entire HA/DR infrastructure, regardless of the operating system, virtualization technology, underlying server and storage hardware, etc. What organizations need is a solution that works for each specific application or platform. By standardizing on a unified platform for both physical and virtualized environments, organizations can reduce training costs, increase employee flexibility, and reduce the burden on administrators by providing a single platform for system configuration.

Finally, when choosing a high availability and disaster recovery (HA/DR) solution, IT organizations should look for solutions that have advanced virtualization features from server virtualization vendors who can provide virtualization tools for planned maintenance and workload balancing. IT managers should only purchase high availability and disaster recovery (HA/DR) technology to take advantage of all the features of server virtualization technology. A high availability and disaster recovery (HA/DR) solution enhances the availability of the IT environment by providing powerful control and visibility.