In a(n) only the objects that have been updated or modified since the last full backup are backed up.
a) transaction log backup
b) differential backup
C) adaptive backup
D) conservative backup
The correct answer and explanation is:
The correct answer is b) differential backup.
A differential backup is a type of backup where only the objects or files that have been updated or modified since the last full backup are backed up. It allows for quicker backups compared to a full backup because it does not include all files but only those that have changed. This type of backup is especially useful for minimizing the amount of storage space used and reducing the time it takes to perform the backup.
In a differential backup, the system will record all changes made since the most recent full backup. This means that, unlike incremental backups, which only capture changes since the last backup (whether full or incremental), differential backups accumulate changes and grow larger as more time passes between full backups. However, because only one full backup is required to restore a system, and then the most recent differential backup, it strikes a balance between recovery time and storage space usage.
For example, let’s assume a full backup is performed on Sunday. On Monday, some files change, and a differential backup will capture all changes made since Sunday. On Tuesday, more changes occur, so another differential backup is taken, which now includes all changes from Sunday to Tuesday. This continues until the next full backup.
The advantage of using differential backups is that the restoration process is relatively fast because only two sets of data—the full backup and the latest differential backup—are required to restore the system. However, as more time passes between full backups, the size of the differential backup grows, which may eventually require more storage space. This type of backup strategy is a common choice in environments where frequent backups are necessary, but a full backup every day would be too resource-intensive.