Efficient disaster recovery strategies

Laurent Dedenis explains how virtual standby systems increase system availability.

"Anything that can go wrong, will go wrong. It's only a matter of time." Finagle's Law, often confused with Murphy's Law, is a favourite among pessimists, and is known for coming true whenever you least expect it. Laws with such impressive logic don't fall on deaf ears in the IT departments of companies. Therefore "be prepared" is the motto. However, if you take a look inside many organisations’ server racks and rooms, it quickly becomes clear that if something goes wrong there, downtime is looming.

CEOs often baulk at the idea of purchasing standby systems for their servers, which would allow for fast resumption of business activities in the event of any hardware or system failure. Indeed, prices are effectively doubled if you create server redundancy to allow for high availability. It is also argued that regular upgrades must be performed on an increased number of machines, which ultimately increases administration costs.

The latter argument is already invalid, because imaging technologies can mirror server operating systems on the fly, and images of the server are regularly and automatically created by a task planner. This means that the standby hardware must only remain available, and does not require any additional maintenance. At least this is the case if it is feasible for the organisation to cope with a small data loss whilst performing disaster recovery. Under these conditions, it is possible to recover the current, complete image of the server operating system to the replacement hardware, and boot up the server. The server is available quickly and can be used just like its ailing twin, without performing additional settings.

The argument about the high cost of standby hardware remains. With the increasing adoption of virtualisation solutions, an alternative scenario has emerged that enhances disaster recovery strategies, and can now be implemented economically and effectively in organisations of all sizes. Implementing such a strategy only requires a high-performance replacement server. With the aid of a converter, the system images of all the physical servers are transformed into virtual hard disks for virtualisation platforms like VMware, Parallels or Virtual PC, Microsoft Virtual Server and XenSource. The virtualisation solution is installed on the standby server. In the event of a disaster, all that is required is to boot the virtualised system on the standby server. A single server can therefore serve as a stopgap measure for all of the systems. The homogenised platform of the virtualisation solutions offers a home for all of the server operating systems required within the organisation. While the tasks of the failed system are being performed in the virtual environment, the administrator can use the time gained to replace the defective hardware.

However, there are some cases in which this scenario does not work. When database applications require their own physical server, or if exotic interfaces are needed which current virtualisation solutions can't provide, the traditional route using duplicate hardware will still be required.

Going back to our disaster scenario, in order to switch back from the emergency virtual machine to the physical server which has now been replaced, an image of the virtual server is created and then recovered to the physical hardware. To recover to dissimilar hardware or migrate between physical and virtual environments (P2V2P), Acronis offers a module called Universal Restore. The above-mentioned converter for image files is a key component of the Acronis True Image Echo Corporate Solutions. A leader in virtualization, VMware offers the option in its converter to transform True Image archives (.TIB) directly into virtual hard disks.

Virtualisation has revolutionised disaster recovery – increasing time and space efficiency, while providing affordable, flexible and reliable recovery that can even be performed remotely. If utilised correctly, a virtualised server can provide protection superior to physical backup at a fraction of the cost of hardware-based solutions.

Laurent Dedenis brings more than 15 years of experience in start-up management across the United States, EMEA and Asia. Responsible for Acronis’ international operations and for driving growth in EMEA, Dedenis oversees the distribution strategy, sales and marketing functions as well as product localisation.