The Least Amount of Backup Sets Required for Server Restoration
Question
A server failed Thursday evening before the nightly backup.
The backup scheme in place was full backups every Sunday, incremental backups on Monday, Wednesday, and Friday, and differential backups on Tuesday, Thursday, and Saturday.
To fully restore the server, which of the following is the LEAST amount of backup sets required?
Answers
Explanations
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A. B. C. D.C.
To fully restore the server, we need to have the data as it was just before the server failure. Let's analyze each backup type and see what data it contains:
- Full backup (Sunday): Contains all data on the server. This backup is not useful since it was taken before the server failure.
- Incremental backup (Monday, Wednesday, and Friday): Contains only the data that has changed since the last full or incremental backup. Since the server failed on Thursday evening, the incremental backup taken on Friday will not include any data from Thursday.
- Differential backup (Tuesday, Thursday, and Saturday): Contains all data that has changed since the last full backup. Since the server failed on Thursday evening, the differential backup taken on Thursday will contain all the data that was on the server before the failure.
Therefore, to fully restore the server, we need the following backup sets:
- Full backup (Sunday)
- Differential backup (Thursday)
We do not need any incremental backups because they do not contain the data that was on the server before the failure. Therefore, the least amount of backup sets required is two: one full backup and one differential backup.
Answer: B. Two.
