According to Gartner, large companies lose $300,000 for every hour of downtime they encounter. These kinds of losses can occur regardless of whether your organisation uses physical or virtual servers, so a good disaster recovery plan is essential in every situation. Fortunately, the recovery of virtual servers is easier than their physical counterparts, so how do you go about building disaster recovery into your virtualisation strategy?
Focus on file backup
Your virtual installation manifests as a group of files on the hard drive of the host server. Any disaster recovery plan needs to ensure that you regularly back up these files.
If your virtual servers are configured to use dynamically allocated virtual hard drive space, you will need to try and calculate the expected rate of growth and specify a backup routine that can cope. Ensure that you have sufficient performance for backup windows and adequate disk/tape capacity to cover your backup needs at the time of deployment and further into the future as your data storage needs increase.
Keep accurate records
The file-based nature of virtual servers makes it relatively easy to define which items you need to back up in your environment. However, for the speediest retrieval of data in the event of a disaster, you will need to know how to reconfigure your missing servers.
It is extremely important to keep full records of your virtual server set up so that you can configure a new machine and restore data directly into it. Your records need to include full details of information like processors, virtual RAM, hard drive space and network configurations. As well as keeping records of the configuration at the time of deployment, best practices dictate that you should also update your server setup document every time you make a configuration change.
Prepare for the worst
Accidents can and do happen. Your hard drive image corrupts, the backup media fails, you delete a virtual machine in error or the RAID array hosting server data crashes – virtually anything can take your servers out of action.
Obviously, a good disaster recovery plan tries to identify and mitigate these risks up front, but a combination of errors and failures could expose flaws in the plan. At this point, you should have the ultimate reserve – a data recovery option to extract ‘lost’ data from hard drives. A tool like Ontrack EasyRecovery could help if your backup lets you down. Alternatively, you can speak to a reputable data recovery company.
Use the right backup software for your virtual environment
There are various backup software solutions on the market. Some are available to use both with VMware and HyperV solutions. The main factor to consider when choosing your backup software is how much time is needed to recover virtual machines (VMs) out of the backup and the VM templates. Additionally, good backup solutions for VMs are able to mount the backup while the files are transferred back to the main host system.
A snapshot is not a backup
Always create backups if you want to make sure that everything is recoverable in the event of a failure. Create snapshots if your changes are very important, and you don’t want to lose any data; this will cover the time frame between the last and the next backup. If you use snapshots, don’t try to build snapshots that build on each other, as this not only reduces performance but makes them more susceptible to error.
Don’t save backups and running VMs on the same storage
If you save your backups on the same hard disk or storage space as your active VMs, you risk ending up with losing all your data. If a backup fails and a VM is active, it will likely overwrite the backup. To prevent this from occurring, always store your backup VMs and your active VMs in different places. It also makes sense to make multiple backups and store them on a different local server/hard disk, whether in the cloud or on tape. Having two additional backups will help you in the event of a data loss.
Don’t try to mix virtualisation solutions
Using several virtualisation solutions in the same environment can increase the risk of data loss. If, for example, a VMware system on one SAN is expanded onto a second SAN that is used by HyperV, there is a high chance that the second SAN will be subject to severe data loss. Such data loss will occur because of the different layers that the virtualisation tools create when they are linked or expanded. Therefore, it is better to keep your virtualisation simple and stick to one solution within a given environment. Adding too many layers of complexity can be very risky and will make any needed data recovery time consuming or not possible at all!
Think and plan before you use VMs
Always keep in mind that virtualisation and virtual machines are not error-free and are as likely to fail as other storage options. Therefore, before you create a virtual environment for sensitive applications, think about what is most suitable for your organisation’s needs. For example, some applications have a high input/output (I/O) rate and are, therefore, a better fit for physical server environments.
Many of today’s virtual platforms include data protection and recovery mechanisms, but you would be wise not to rely on them. They may claim to protect you from data loss, but they are not a replacement for a proper backup strategy.
But remember…
Even if you implement the above five essential tips, there is still a chance that your virtual machines could experience data loss. It is therefore essential that your IT department is fully aware of the ins and outs of your systems, and have a specific plan on how to react in case of failure. Every organisation should have a data recovery company on speed dial; downtime and the loss of data can be extremely costly for an organisation, so ensuring a specialist is on hand to help is vital to ensure the recovery of valuable data.
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