General Question About Full and Incremental Backups

You may find this link of interest.
http://forum.acronis.com/forum/27844#comment-86265

The preferred backup would have been a full backup each time. The reason being is that a full backup is a standalone backup and does not need other backups to be used. Each of the incrementals need the full so if the full becomes non-readable or corrupt, then the neither of the incremental has any value.

Assuming that all the backups are readable and none are corrupt, then you have no issues with the backups. Each or all can be restored and put your computer back to the same point as when the backups were created.

For example, if you wanted to restore you system back to before you created any incrementals, you would choose and restore just the first full backup. Or, if you wanted to restore back to the same point as when you created the first incremental, it would choose the first incremental to be restored and the program would first restore the full and then the first incremental. Or, if you wanted to restore back to the same point as when you created the 2nd or last incremental, then you would choose the second incremental as to what was to be be restore and the the system would first restore the full and then the first incremental and then restore the second incremental. Should you want to create a duplicate disk, you would choose the second incremental to be restored and the program would restore the full plus the first plus the second.

John Porterfield wrote:

Before I ask my question, let me explain what I did.

I reformatted my laptop. I made an initial FULL backup image of the initial OS with all updates. Next, I installed all my applications and made an INCREMENTAL backup image. Finally, I tweaked my system and customized/personalized all of my settings, and made another INCREMENTAL backup.

A friend told me I should have just done three full backups. Is this true?

No. It is not true. You are perfectly fine.

If my hard drive ever crashes, I will have to install all backups, both full and incremental, in consecutive order, correct? I mean, I can't just install an incremental, right?

When you restore, you point ATI at any backup, typically based on the date you want to restore up to, full or incremental, and ATI will sort it out.

Lastly, in the future when I do routine backups, should I continue incremental or just do a full? (I plan on keeping five images max, deleting an older one when a recent one is made.)

The rule of thumb is that you shouldn't do a chain of incrementals too long for you to go back to the last full backup if you had to. The reason behind this rule of thumb is what Grover explained. In a chain of incrementals, each backup, starting from the first full of chain, including all incrementals up to the one you restore, have to be present and not corrupted. Validating you backups helps identifying corruption issues. If for any reason, the first incremental after the full gets corrupted, any backup afterwards is useless. That said, corruption issues are rare, and even rarer if you do regular validations.
Because of the perceived risk around incrementals, some people choose to do only full backups, or do differential backups. But both methods can be prohibitive for big disks and/or with constrained backup space.
At any rate, if you change the backup scheme, retention rules, backup name or destination, create a new task.

Very informative guys, thanks! Is there a way to take my two incrementals and make them fulls? For example, I have my original full. Can I take that and merge it with my first incremental to make a second full? And then take that second full and merge it with my second incremental to make a third full?

Managing multiple generations of backups (1 full plus n incrementals or differentials) is made bulletproof with the batch files I posted recently, which provide fine-grained control of any number of backup generations. You would be well advised to use them instead of trying to do it in ATI.

See http://forum.acronis.com/forum/27989 .

@john,

Technically you can use the consolidate versions feature of ATI. This will fold an incremental into a full, or several incrementals into a full. Of course the data of each incremental will replace the older data in the backup. In other words, if the full had V1 of a file and the incremental had V2, the consolidated version will have only V1.
Consolidation is a lengthy process that requires a lot of free disk space to run: as much as the size of the biggest backup to be consolidated.
I personally stay away from consolidation: not worth it if you have enough backup space...

What Happens if I do a full back-up and then do an incremental backup every day using the initial full backup as the source file every day. Is this not the same as doing a differential backup. Presumably I could get back to the initial full backup by restoring the inital full back and the last incremetal backup. Or does the incremental backups only restore back to the previous incremental backup even though I select the inital full backup as my source file.

Hello John,

thank you for your question.

In case you start a separate task to create an incremental backup, selecting a full one each time, then it will be absolutely similar to the differential backup.

Incrementals are useful in case you want to keep an ability to restore to several points in time, and still have free space. But incremental backup depends on all the previous versions created in the same chain. For instance, if you have Incremental A1, Incremental A2, and incremental A3, and A2 got corrupted: you will not be able to restore A3.

I'd advise you to check this KB article for more details regarding differences between Incremental, Differential, and Full backups.

If you have any questions - let us know, we will be glad to clarify the situation.