Disaster Recovery Question

amart83

You need to design a backup plan. You want to design a backup plan that uses the minimum amount of tapes to restore.

Options:
-Normal
-Daily
-Differential
-Incremental

Drag and Drop:
Monday - Tuesday - Wednesday - Thursday - Friday

I answered: Differential Monday thru Thursday, and Normal on Friday.

Thoughts?

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Comments

genXrcist

I'd say Normal for Monday and Incremental for the rest since it requires the least amount of space. Less space = fewer tapes.

Honky007

This question stumped me, I mean they don't tell you what day you are starting from.

Normal on Friday and Diff. for the other days seems logical doesn't it?

I'm not sure what the Microsoft answer is!

Normal everyday seems excessive...

amart83

The answer I went with was "Differential" for Mon-Thur and "Normal" for Friday.

Here's from Microsoft TechNet article Link:

Backing up your data using a combination of normal backups and incremental backups requires the least amount of storage space and is the quickest backup method. However, recovering files can be time-consuming and difficult because the backup set might be stored on several disks or tapes.

Backing up your data using a combination of normal backups and differential backups is more time-consuming, especially if your data changes frequently, but it is easier to restore the data because the backup set is usually stored on only a few disks or tapes.

amart83

Honky007 wrote: »

This question stumped me, I mean they don't tell you what day you are starting from.

Normal on Friday and Diff. for the other days seems logical doesn't it?

I'm not sure what the Microsoft answer is!

They don't, I double checked just to make sure they dropped a hint that I didn't see.

Don't know if it mattered when the Normal backup was done (Mon or Friday?) but usually it's done at the last day at the end of the business week so I went with Friday.

skrpune

amart83 wrote: »

They don't, I double checked just to make sure they dropped a hint that I didn't see.

Don't know if it mattered when the Normal backup was done (Mon or Friday?) but usually it's done at the last day at the end of the business week so I went with Friday.

I'd have to agree with you on your choices of Normal on Friday & Differentials on the other days.

Normal/full backups take a long time and are usually done on a weekend or at the end of a week, so I'd say a normal backup on Friday is almost certainly a given here.

You want to have the fewest tapes to restore, so if you have that normal backup in hand, doing a differential backup on every other weekday will mean that if you want to restore on any given day, you'll just need that Friday normal backup tape + the last differential backup done and you're set.

royal

No, the answer is Normal every day. MINIMUM number of tapes to install. You do a normal backup every day and you only ever need to use 1 tape to restore by restoring your normal (full) backup.

Normal + incrementals would require a normal restore and every day's incremental backups. This wouldn't be as fast as doing a single normal restore and would still require you to restore more data in the long run since you'd have to do a normal restore and all the incrementals. You would need A LOT of tapes for this.

Normal + differential would need only 2 tapes.

Normal every day would require all data to be backed up every day. Because of this, it would require only 1 tape to ever restore. Because of this, it uses the least amount of tapes to restore.

amart83

royal wrote: »

No, the answer is Normal every day. MINIMUM number of tapes to install NOT fastest restore which is why incremental backups would be wrong. You do a normal backup every day and you only ever need to use 1 tape to restore by restoring your normal (full) backup.

Had a feeling, but the "clearing of the archive" part was throwing me off. Went back and read up all about backup and felt more confident it was normal every day.

Thanks royal.

Honky007

Yeah, i guess that would be the answer, but it still doesn't make sense in a real-world sense

genXrcist

royal wrote: »

No, the answer is Normal every day. MINIMUM number of tapes to install. You do a normal backup every day and you only ever need to use 1 tape to restore by restoring your normal (full) backup.

Normal + incrementals would require a normal restore and every day's incremental backups. This wouldn't be as fast as doing a single normal restore and would still require you to restore more data in the long run since you'd have to do a normal restore and all the incrementals. You would need A LOT of tapes for this.

Normal + differential would need only 2 tapes.

Normal every day would require all data to be backed up every day. Because of this, it would require only 1 tape to ever restore. Because of this, it uses the least amount of tapes to restore.

Doesn't this answer assume you can fit an entire Normal backup on 1 tape? If a Normal backup requires 10 tapes, and you only add incremental backups thereafter, in the end wouldn't you have fewer tapes? I am assuming multiple incremental backups would fit onto any one tape.

Nuwin

I don't think it assumes a single tape, but we just reference it becuase it is easy. The key is the minimum number to restore. Anything outside of normal would put you at normal backup + incremental/differential tapes.

meadIT

genXrcist wrote: »

Doesn't this answer assume you can fit an entire Normal backup on 1 tape? If a Normal backup requires 10 tapes, and you only add incremental backups thereafter, in the end wouldn't you have fewer tapes? I am assuming multiple incremental backups would fit onto any one tape.

Even if a Normal took more than one tape, it would still be the correct answer.

Example: Normal + Incremental restore...you would need the 10 tapes from the Normal + How ever many an incremental took, so let's say 10 + X. A Normal backup every day would only require 10 tapes, so 10 < 10 + X. A Normal backup every day is still the correct answer because they specifically ask for the least amount of tapes to perform a restore.

meadIT

Honky007 wrote: »

Yeah, i guess that would be the answer, but it still doesn't make sense in a real-world sense

Exactly. One of the first things to learn when doing MS tests is to throw every "real world" idea out the window and just answer the questions to fulfill the requirements stated.

genXrcist

meadIT wrote: »

Exactly. One of the first things to learn when doing MS tests is to throw every "real world" idea out the window and just answer the questions to fulfill the requirements stated.

Gotcha, that makes sense. Truth be told, I would never have answered that way on the test!

Good question!

puertorico123

asuming for small domain, you requiered to restored, 1 tape of full back-up + 1 diferential. but if a medium domain + file server, 2 tape of full back-up + 1 diferential.