Exam SY0-501 topic 1 question 42 discussion

guys there are 3 kinds of backups a full backup which backs everything up , an incremental backup which backs that have been saved on the pc for that day , and if done again the next day it will again only back up the things that have been saved on the pc for that day. and finally there is the differential backup which will back up all the files that have been modified or saved since the last full back up so if you do a full backup on Sunday , and you do a differential backup on Monday the differential back will backup everything on the computer that was modified(edited, deleted or whatever) in addition to new things that was saved on the computer from sunday to Monday, and if you do another differential backup on Tuesday it will back all the things from Sunday to Tuesday so if you have to restore on Wednesday you will only need two backups the full backup from sunday and the differential backup from tuesday since that backup contains everything that happened from Sunday to tuesday .

Only need to install one full back up and one differential backup from Tuesday morning at 2am. The full back up happened Saturday. No one typically works weekends so no differential backup needs to happen Sunday at 2am or Monday at 2am Since those cover the weekend

Thrown off by the Sunday backup. So: Saturday Full Backup (1) Sunday Diff Backup (2) Monday Diff Backup Restore on Tuesday. the answer is 2

***Remember - Differential is ALWAYS two backups to restore.*** Differential is a complete backup of the 'differences' from last full backup. Incremental is changes since the last incremental backup. So, differential restore = full backup plus one differential. Incremental restore = full backup + incremental 1 + incremental 2 etc. Usually a differential will be used as daily backup, with incremental backups used during that day so you have near real-time backup copies, and a full backup once a week, which then get archived in a Grandfather-father-son backup system

A database backup schedule consists of weekly full backups performed on Saturday at 12:00 a.m. and daily differential backups also performed at 12:00 a.m. If the database is restored on Tuesday afternoon, which of the following is the number of individual backups that would need to be applied to complete the database recovery? The weekly backup is done on Saturdays at 12 am. This means once in a week. Daily back up which I assume to be from Monday-Through Friday back up is done at 12am. Weekday beings on Monday @12am +1 and Tuesday @ 12am +1. Monday + Tuesday = 2 days. I hope this makes sense.

Answer: 2

At first i thought the answer was 3, but the catch is on the type of backup; see this from Wikipedia: A differential backup is a cumulative backup of all changes made since the last full backup, i.e., the differences since the last full backup. The advantage to this is the quicker recovery time, requiring only a full backup and the last differential backup to restore the entire data repository.

Think of it this way: differential results in more time spent on backups but less time on restoring while incremental results in less time spent on backups but more time spent on restoring.

Thrown off by the Sunday backup. So: Saturday Full Backup (1) Sunday Diff Backup (2) Monday Diff Backup Restore on Tuesday.

B. The differential backup accumulates all new and updated folders and files since the last full backup. So all you need is the last full backup and the most recent differential backup.

When you're doing differential backup and you need to restore data, you'd only need the Full backup and the LAST differential backup you did so the answer is 2

It's 2 because it's full backup on SAT and DIFF on everyday. Event we have to restore on Friday we still need only 2 individual backups. Read this: https://www.easeus.com/backup-utility/differential-backup-vs-incremental-backup.html

Author of the question assumes No Work on Sunday, which I don't agree. That's not a universal rule. It should have been worded differently.

yah it's 2 bclz diff. backup need to be stored individually since last full back. Rectify is i'm wrong.

I don't understand the answer. It's two back ups: the first full back up on Saturday and then the differential backup on Tuesday which backed up everything between Saturday and Tuesday?