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Hardware failure is inevitable
To combat the erosion of data and the failure of systems, backup procedures must be designed to account for the eventual failure of a computer?s hardware. Computer hardware has a finite lifetime. And electronic media is transitory because it must continually be juggled from one storage device to another during its lifetime. While many system failures do not involve hardware failure, those that do must still be addressed in a timely and cost-effective manner. Even if the hardware must be replaced, the need for a rapid system recovery solution exists. Bare metal recovery has two major approaches: automated and manual. Each approach has its uses.
Automated system recovery
Automated bare metal recovery is designed for rapid, systematic recovery. By using automation, procedures are more likely to be predictable and simple. The user will not require as much training, and therefore, the automation approach should also be more reliable. Automated Windows system recovery does, however, have limitations. Because an operating system, with its unique configuration, is designed at the time of installation for a specific hardware device, an automated recovery cannot account for dissimilar hardware components at the core of the new computer system.
The most problematic components are the Windows HAL, or Hardware Abstraction Layer; the kernel; and storage controllers. When a Windows system boots, these three elements must be correctly assigned to the hardware, or Windows will not boot. Solving additional device conflicts are less critical because, once loaded, Windows makes these devices easy to detect and install.
Manual system recovery
Because of the dissimilar hardware limitations of an automated recovery, many users choose a manual reinstallation of the operating system. For instance, in the past when one of the key hardware components failed?storage controller, motherboard, processor, HBA?manual recovery was the only viable approach. By reinstalling the operating system manually, each of these items will be detected and installed in a clean environment. The drawback, of course, is that the system must now be configured entirely from scratch. Service packs and hot fixes must be applied.
Applications must be installed and configured. System settings must be set to match company standards. All this before restoration of data can begin. The complexity of this process is beyond ad hoc management techniques and requires strict controls and procedures.
When preparing for bare metal recovery to dissimilar hardware, users will commonly keep a journal intended to account for each of the changes that have occurred on the computer. This manual method of bookkeeping is tedious and often fails to account for many system changes. In addition, some administrators will capture the most recent ?cold image? of the system during the infrequent occasions when that system can be offline. These steps amount to a significant management effort just in planning for system recovery. And the result is still a painfully slow recovery.
Manual recovery relies on multiple steps following a layered approach that is intended to restore the system as closely as possible to its prefailure state. If ?cold images? were captured, then the most recent one can be recovered as a starting point. But all changes since the last image will still have to be accounted for manually.
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