Backup and Restoration

Correct Answer: Restore the last full backup and then the differential backup

The optimal recovery technique after an unexpected power outage is to first restore the last full backup and then the most recent differential backup. Let's break it down: - Full backups include every bit of the data as of the time of the backup, while differential backups only back up the data that has changed since the last full backup. - Restoring only the most recent differential backup (without the last full backup) doesn't contain all the necessary data because it'll be missing all the data that has not changed since the last full backup. - Restoring only the last full backup, on the other hand, misses all the data changed after that full backup up to the point of the crash or outage. - Restoring the last differential backup, then the last full backup will lead to inconsistency and missing updates because it won't correctly apply the changes made after the last full backup. The correct sequence is to first restore the original full backup, and then apply the changes from the differential backup.

Correct Answer: Restoring the last available backup and applying incremental backups, if possible

The best restoration strategy to minimize downtime when a critical server doesn't have a recent backup is by 'Restoring the last available backup and applying incremental backups, if available'. This is because restoring the last available backup provides a foundation from which the system can start functioning again, whilst applying incremental backups will bring the system back to the most updated state possible. The other options would potentially result in longer downtime and more data loss. 'Wiping the server and performing a clean installation' would typically result in significant downtime and a complete loss of data. 'Attempting data recovery from the server's hard drive' can be a slow and uncertain process, which might not be reliable depending on the cause of the issue and the state of the drive. And finally, 'Restoring the last available full backup only' is also a viable option but it would leave out any changes that were made after that full backup was created, potentially leading to data loss.

Correct Answer: Restore the latest full backup and then apply incremental/differential backups, if available

The best next step in the restoration process after a catastrophic event and with all hardware and software replaced at a secondary site would be to 'Restore the latest full backup and then apply incremental/differential backups, if available'. This is because after a catastrophic event, data integrity is the first priority for a datacenter. Restoring the latest full backup ensures that as much data as possible is recovered, while applying the incremental/differential backups ensures that changes made after the last full backup are also restored. The other answers are incorrect: Performing a clean installation of all software and starting data collection from scratch would result in a loss of all pre-existing data. Restoring only the latest incremental/differential backup leaves out potentially critical data from previous backups. Avoiding restoration and using the hardware assets for another purpose does not address the immediate need to restore the datacenter to operational status.