Switching to a different backup application can be a seriously challenging experience. Not only is there usually a learning curve associated with adopting a new backup application, but there is also the question of how to restore old backups. After all, it is conceivable that a data loss event may require you to restore data that exists only on your legacy backup system.
Unfortunately, there’s no universal solution to this problem. Every organization is different, and each has its own unique backup architecture. The backup architecture plays a major role in what the admin must do to restore old backups.
Suppose for instance that an organization runs its backup application on a physical machine that is connected to a physical tape drive. In such a situation, the best course of action would be to unplug the computer that runs the backup software, label the computer, and store it in a safe place.
While it might be tempting to reuse the old computer for running the new backup application, doing so would probably require the legacy backup software to be removed so that the new backup application can be installed. This means that if an older backup ever had to be restored, the backup administrator would have to remove the current backup application, install the legacy backup application and any applicable licenses, rebuild the indexes, restore the data, remove the legacy application, and reinstall the current backup application. This process is not only time consuming, it is potentially problematic. For instance, what if the installation media for the legacy backup software cannot be located? What if all of the license activations have been used up, and you are prevented from completing the installation? What if newer OS updates cause the legacy backup application to experience problems?
If your backup application is currently running without issue, then it is much safer to retire the entire machine, and put it in storage in case it is ever needed, than it is to install new backup software onto an existing backup computer.
Granted, in the real world the IT budget might not allow a legacy backup computer to be replaced. If that is the case, then you should remove the existing hard disks and store them in a safe place. If the legacy backup application is ever required, you can always reinstall the hard disks.
Given a choice, it is preferable to replace the entire machine than to simply replace the hard disks. The reason for this is that the hard disks containing the legacy backup application assume that the computer is equipped with a specific hardware configuration. If parts are replaced over time, then the legacy operating system may no longer recognize the hardware and could fail to boot, or may require some new device drivers in order to function. Of course, there is also the durability factor to consider. A computer is probably less likely than a hard drive to be accidentally knocked off a shelf and broken.
As previously mentioned, an organization’s backup architecture is usually the determining factor in how the organization must plan to restore old backups. If an organization runs its backup software on a virtual machine, then protecting the ability to recover legacy backups may be as simple as powering down the existing backup VM and ensuring that the VM remains adequately protected.
Of course, it isn’t just the backup server that must be protected. The backup media and supplementary hardware also require protection. This is easy if an organization is performing tape backups because existing tape drives can either be stored or reused. Things become trickier, however, if the backup target is disk based.
In the case of disk-based backups, the best course of action is to simply power down and unplug the storage array so that it will remain undisturbed. However, storage hardware can be expensive, so decommissioning a storage array might not be an option. If a storage array must be reused, then it may be possible to install additional disks, which isolates new backups from legacy backups. If not, then you may have to use the legacy backup software to dump the backup data to tape so that the storage array can be repurposed.
If you follow this course of action however, be sure to test your ability to recover from tape. Some backup applications require the tape to be imported into a storage array before the backup data can be used.
As you can see, there is no such thing as a universal solution for protecting legacy backups following an upgrade to a new backup application. As such, it is important to adopt a solution that is well suited to your own organization’s backup architecture.