Important Questions

Sorry friends, this backup stuff is new to me and I have to ask some basic questions. I've read the manual, but I still need direction.

I recently purchased 2 external HDs and used Windows Explorer to copy the same data files from one drive to the other (It took a while, but I was paranoid about losing files). My goal is to simply backup my active data files to the 2nd drive for maximum security.

Should I have mirrored the 1st drive to the 2nd with Acronis True Image 9.0, instead of starting out using Windows Explorer? Does it make any difference, now that I want to start backing up? Can I start backing up w/o having the
1st drive mirrored, as long as the same files are there?

If I do need to go back and mirror, do I have to take off all the files on drive 2?

Then, when I have everything ready, is differential or imcremental best if I already have a lot on the drives?

Thanks,
Bill

 

Hello Bill,

Thank you for your interest in Acronis Disk Backup Software.

Acronis True Image 9.0 allows you to solve all backup problems, ensuring the safety of all information on your computer. Using it, you can back up selected files and folders, or entire disks and partitions.

You can create the image of your first hard drive to the second one instead of using Windows Explorer.

Please note that when you create an image of your first hard drive to the second one, you do not need to have first drive mirrored, because all data is included into image archive.

Please note that there are two approaches available:

- Incremental backup contains all data modified since the last preceding backup (full or incremental). To restore from an incremental backup, you need to have the full backup and all preceding incremental backups, if any.

- Differential backup contains all data modified since any preceding backup (unlike incremental backup that contains data from the last backup only). To restore from a differential backup, you need to have all backups preceding the backup being restored.

Please find more detailed information about incremental and differential images in this FAQ article.

You can also find an additional information about differential and incremental backups in Acronis Solutions article.

Please download Acronis True Image 9.0 trial version at http://www.acronis.com/homecomputing/download/trueimage/ in order to check how the product works.

Please visit Acronis online store to purchase the full version of the product.

If you have any further questions please feel free to ask.

Thank you.
--
Tatyana Tsyngaeva

 

Hi Tatyana,

Would you please clarify this previous statement of yours:

- Differential backup contains all data modified since any preceding backup (unlike incremental backup that contains data from the last backup only). To restore from a differential backup, you need to have all backups preceding the backup being restored.

It left me confused - it's not as I understand the FAQ or the User's Guide.

Thank you.

 

The FAQ says about restoring from a differential backup:
"A differential image contains all changes that have been done after the full image creation. To restore a differential image, Acronis True Image must match the differential image with the original image."

This matches my understanding from other programs. The last differential contains all the changes from the time of the original backup and you only need to restore the original and the last differential - not all the differential backups.

Like another program says: incremental: quick to do, slow to restore (you have to restore them all); differential: slow to do (you have to copy all the changes each time), fast to restore (only one file after original).

 

Hi seekforever,

My understanding fully matches yours. Of course, it matches also what is said in FAQ and User's Guide, since it originates from there. But Tatyana's statement above is at least ambiguous to me.

I hope Tatyana will notice this discussion and jump in to clarify.

 

Hello everyone,

Thank you for choosing Acronis Disk Backup Software.

Please accept my apologies for not being accurate enough in my explanations.

Acronis True Image 9.0 allows you to create not only a differential backup on the base of the full one. It also allows you to create the differential image on the base of the incremental image and vice versa.

E.g. you can have the following set of backups:



F is a first (full) backup; Ix are incremental backups; Dx are differential backups. In order to restore I4 you need to have D3 and F. In order to restore D5 you need D2 and F. In order to restore D6 you need F only.

If you have any further questions please feel free to ask.

Thank you.
--
Tatyana Tsyngaeva

 

Hello Tatyana,

Thank you very much for this thorough explanation.

That's flexibility par excellence - it really takes a schematic to display. I was completely unaware that such combinations were possible. I wonder how I missed that information.

Shall have to reconsider my backupping strategy, I suppose.

Best regards.

 

LOL You have all indications of making a great politician someday.

Well here we go again...

As Seekforever previously pointed out.

That restore would require D5 and F only.


The industry standard for backup software terminology is as follows:

Full: All files are included into the backup.
Incremental: Only those files will be included which have been changed since the last backup.
Differential: Only those files will be included which have been changed since the last FULL backup.

If Acronis uses different terminology, then I apologize for not being accurate enough.

 

Hello noonie,

Actually, you are almost right. I should note one thing, Acronis True Image 9.0 allows you to choose the source image archive for the next differential backup. This source archive can be differential already and that is why this example appeared (D2 and D5). I mean that a differential backup can be taken from a differential which can be taken from a differential too, and so on.

I hope that my explanation is intelligible. If it is not then please feel free to ask. We'll try to clarify it.

Thank you.
--
Kirill Omelchenko

 

Kirill

That is a very clear explanation. A differential from a differential eh? Who woulda thunk it! It would be very useful if that information was added to the User Guide.

seekforever

It should work out that a differential on a differential would be faster than a normal differential to do and faster than incrementals to restore.

 

She said that to restore D5 you need D2 and F

This is the important distinction:

Can you restore to D5 by using D5 and F only?

If the answer is yes, it is a differential backup.

If the answer is no, and you need D2 as well, then it seems it is really doing an incrimental and just being called a differential.

 

As it seems to me from what I read in this thread, we only have two types of images at our disposal - the Full and the Appended (my naming). There is no third type.

If we select the sources for each consecutive Appended image in a serial pattern (Full -> Appended -> Appended -> ...) , the resulting set of images is a so called incremental set.

If each consecutive Appended image is sourced from the Full, the resulting set of images is a so called differential set.

The first Appended image is undefined in incremental/differential terms, the role it will take depends on the selection of sources for the following Appended images.

If this understanding of mine is correct, it makes no difference whether we select either Incremental or Differential option from the selection screen. Both ways we get the technically same (Appended) image. All the difference stems from the selection of the source for such an Appended image.

And if that is so, the selection screen should really give us only two options (Full/Appended), not three (Full/Incremental/Differential), since the choice between Incremental and Differential imageing is not made there.

Please do correct me if I'm wrong.

 

I think, after reading your post a couple of times that you are technically correct. However, differential and incremental are standard terminology in the backup universe and trying to introduce a new view of the old picture doesn't really help.

If I know files X and Y are a differential backup files and files A and B are incremental backup files then I know what I have and what I have to do to restore my system.

 

Hi seekforever,

In the absence of opposing comments to my previous post I would like to add:

- The possibility to create fully flexible free-pattern backups looks great at first glance, but when I think it over, the added benefit may not be worth the risk of having a needed .tib file in the chain deleted by mistake. I therefore tend to agree with Acronis' decision not to promote this approach in the User's Guide.

- The standard incremental and differential techniques should satisfy most needs. I think that both incrementals and differentials are true to definition if created as directed by TI. The difference is that with file oriented backupping software you make the selection in one step and you are off (thanks to the archive bit), while with sector oriented TI it takes two steps (appended vs. full + sourceimage selection).

- Supposing that I now understand (?) the mechanics involved in the TI backupping process, I would just like to see, Dear Support, some improvement in the section of GUI concerning selection of backup type. In my opinion, the selection screen should display only two buttons, (Full) and (Incremental/Differential), as well as the underlaying logic supporting the directions for the selection of the correct source image. I'm sure that the popup reminder (that can even be disabled!) is way below par here.

 

http://C:/test.jpg

I have repeatedly tried to create a differential backup image using a differential image rather than the original full image archive as the base. As far as I can tell, I have not been able to succeed.

Moreover, in the Schedule Task Wizard under Archive Creation Mode, when Differential Backup is selected, it says "Backs up only changes occurred since a last full backup." and it says this whether I select the full backup archive as the base or a differential backup archive. Therefore, if your statements are correct, then the information in the dialog box is wrong.

You might also want to take a look at the thread called Problem with Differential Backups because it appears that there is a problem with the image verification routine for differential backups.

 

Hello HW11,

Thank you for choosing Acronis Disk Backup Software.

Please accept our apologies for the delay with the response.

Please take a look at my reply in this thread.

Thank you.
--
Alexey Popov

 

Alexey, thanks again for your reply regarding the verification of differential backups. However, I would also appreciate a reply to my question about how to force the program to do a differential backup of a differential backup. In Kirill Omelchenko's message on February 9, 2006, he specifically states that

"Acronis True Image 9.0 allows you to choose the source image archive for the next differential backup. This source archive can be differential already and that is why this example appeared (D2 and D5). I mean that a differential backup can be taken from a differential which can be taken from a differential too"

Thank you

 

I would be grateful too, if Acronis Support commented on the deductions I drew from the statements in their early posts in this thread and summed up in posts #12 and #14.

Due to the absence of any opposing comments at that time, I assumed my conclusions to be correct, but reading what followed recently I'm not so sure any more.

Many thanks.

 

Hello HW11, bVolk and everyone interested,

Thank you for choosing Acronis Disk Backup Software.

I'm afraid that the above posted scheme is not correct. The point is that each new differential backup depends on the initial full backup only. There is no way to create differential backup based on another differential or incremental backup. In other words Acronis True Image 9.0 does not allow you to "choose the source image archive for the next differential backup", but analyses the already existing set of images (full plus a number of incrementals or\and differentials) automatically in order to determine the base image for the next differential backup (in fact initial full image). We are really sorry for misleading all of you. We will certainly do our best in order to avoid such mistakes in the future.

Thank you.
--
Alexey Popov

 

Alexey, thank you for that clarification. Personally, I am quite content with True Image doing differential backups the same way as any other backup program I have used over the years. It avoids a lot of potential confusion.

There is just one other related matter you may want to deal with. In order to avoid more confusion, you might want to suggest to your colleagues that they delete their messages in this thread with the incorrect examples. I am referring to messages 6 and 9. In fact, since the analyses in many other messages are based on their comments, you might want to delete every message in this thread, except for your final clarification, message 19.