Backup Type Documentation

[AlanNP]

I'm curious to know the difference between full, differential, and incremental backups. I can't find reference to them in the online manuals. Could somebody please direct my reading?
Alan.

[n8chavez]

Full images - Backs up everything on the selected disks/partitions, not requiring an previous backup.  They are going to be the largest file and take the longest to create.  But they are the safest.

Differential Images - A backup image of the selected disks/partitions that contains only data changed from a previous full image.  It requires a full image for reference.  These file are smaller than fill images but not as small as incrementals, and take less time to create than full images.

Incremental Images - An image of selected disks/partitions that contains only data changed from a previous incremental image.  These backup images require previous incremental images, functioning as a link in a chain.  If one link is bad/damaged the chain is useless.  This image type is going to be the smallest and fastest to create but they are also the most risky, given their reliance on previous incremental images.

Read more about the subject here.

[AlanNP]

n8chavez
Thanks for coming back to me so quickly. I see what the different types of backup are now, and I'm in awe that the software can make these things. Am I correct in thinking a sensible policy would be to make incremental backups until the backup drive is cluttered with them, and then either merge or delete the lot and start again?
Alan.

[n8chavez]

You can do that, certainly. Many do just that. I however prefer weekly full images, followed by 6 days of daily differential images. I think it's safer, and less "chain" reliant. But I've never really had a problem either way.

[admin]

Thank you @n8chavez for your explanation, it is very helpful to Hasleo users and everyone who cares about data security.

The "weekly full + daily differential" strategy recommended by n8chavez avoids excessively long backup chains, while offering high speed and reliability.

@AlanNP, it is certainly feasible to keep doing incremental backups, but as n8chavez pointed out, overly long image chains do carry risks. Therefore, we recommend using an image retention policy or manually merging images to keep the backup chain at a reasonable length.

Thanks again to n8chavez and AlanNP for the discussion. May your data always be safe and sound!

[starchase]

I appreciate the clarification of Incremental and Differential. Please advise if when using Differential and one wants to Restore and has several Differential backups is it true that only one Differential is needed for Restore. I.e., one can safely delete older Differential files and just keep the latest to Restore if desired? This is the way Reflect performs.

Many Thanks.

[admin]

I appreciate the clarification of Incremental and Differential. Please advise if when using Differential and one wants to Restore and has several Differential backups is it true that only one Differential is needed for Restore. I.e., one can safely delete older Differential files and just keep the latest to Restore if desired? This is the way Reflect performs.

Many Thanks.

Yes, your understanding is completely correct. When using differential backups, each differential backup contains all changes since the last full backup, so only the latest differential backup plus the corresponding full backup are needed for restoration. Old differential backups can be safely deleted. The same applies to Hasleo Backup Suite.

Have a nice day!

[al3x]

I appreciate the clarification of Incremental and Differential. Please advise if when using Differential and one wants to Restore and has several Differential backups is it true that only one Differential is needed for Restore. I.e., one can safely delete older Differential files and just keep the latest to Restore if desired? This is the way Reflect performs.

Many Thanks.

Yes, it's exactly the same as with Reflect.

• Differential depends on previous Full.
  
• Incremental depends on previous Differential (and all previous Incrementials after that Differential) or the previous Full (if no Differentials exist).
  

Examples:

• Full -> Diff -> Incr -> Incr
  
• Full -> Incr -> Incr -> Incr
  
• Full -> Diff -> Diff -> Incr -> Incr (wrong, sorry)
  

*Edit: Sorry, last example is wrong. Diffs only depend on full. @admin already answered, was too slow 

[CDC9762]

n8chavez
Thanks for coming back to me so quickly.  I see what the different types of backup are now, and I'm in awe that the software can make these things. Am I correct in thinking a sensible policy would be to make incremental backups until the backup drive is cluttered with them, and then either merge or delete the lot and start again?
Alan.

@n8chavez and @admin have given good advice on this.
My comment for data security is to never only have one complete backup, which can be a full, with any necessary differential or incrementals because your backup disk can fail totally or with a bad sector in the backup image file; even after the backup was created OK.
It's better to keep multiple backups on the drive or much better still, to rotate more than one backup drive.