Macrium: Full and Differential BUs: How do they work?

[Stevekir]

When setting up Macrium (free) to do daily system images I am asked to set the number of Full and the number of Differential backups. I set up 4 Fulls and 4 Diffs, every day. I see on my BU disc only the full BUs. No sign of any diff. BUs! I have a puzzle, as seen in these questions:

A full BU is made on days 1, 2, 3, 4. There are also 4 diff. BUs made on days 1, 2, 3. That's seems to be what my settings mean. The following first three questions all have the same structure but different days:

Q1. On what day does full BU 1 get merged with what diff. BUs. (Presumably on day 2 with the diff. BU made on day 2)? This would mean that full BU 1 was brought up to date just after full BU 2 was made on day 2, but not brought up to date again.

Q2. Similarly, on what day does full BU 2 get merged with what diff. BU. (Presumably on day 3 with the diff. BU made on day 3)? This would mean that full BU 2 was brought up to date just after full BU 3 was made on day 3, but not brought up to date again.

Q3. Similarly, on what day does full BU 3 get merged with what diff. BU. (Presumably on day 4 with the diff. BU made on day 4)? This would mean that full BU 3 was brought up to date just after full BU 4 was made on day 4, but not brought up to date again.

Q4. If so, does that mean that (eg.,) on day 5 (after the day 5 backups had been completed) I could use the full BU that was made on day 2 to restore to the state just after the day 3 backup was made? (The assumption here is that the day 3 diff. BU would have updated day 2's full backup.)

Q5. If not, how could I restore on day 5 using the day 2 BU.

Hopefully, someone could answer "yes" or "no" to each question, before any explanations which would be welcome. Qs 4 & 5 are the important ones.

This is very complicated to get a handle on how it works. We need a diagram.

 

[Norton]

Differential backups don't get merged with a full backup, they are created separately and saved independently.
This is the way I understand Diff and Full BKU. Example of what you would see on the back up disk:
Day 1 Full BK U
Day 2 Differential BK U 1
Day 3 Differential BK U 1 + 2
Day 4 Differential BK U 1+2+3
Day 5 Differential BK U 1+2+3+4
Eventually I believe you would be prompted to create a new full BK U.

I don't use Macrium, but I believe this is how most back up software works. If you wanted to do a full restore you would have to restore the Full BK U + days 2,3,4 and 5.

I don't think there is any advantage to creating 4 Full BK U and Diffs on a daily basis, you are just confusing yourself and wasting disk space.

I know Macrium has good reviews, but I would recommend you try "Aomei Backupper" it has good reviews for a free back up programme, it's user friendly and simple to use. I use Acronis and Aomei back up software. Acronis isn't free

 

[Stevekir]

Differential backups don't get merged with a full backup, they are created separately and saved independently.
This is the way I understand Diff and Full BKU. Example of..................

But Macrium saves to the BU disk only what looks like full backups. No sign of diff. backups:

 

[Norton]

They look like full back up images to me. On the date o2/10/2017 12:48 it appears that you deleted 6.9 GB.

This will explain how Macrium operates.
http://knowledgebase.macrium.com/display/KNOW/Differential+and+incremental+disk+images

 

[Stevekir]

Having successfully fully rehearsed restoring my machine from one of my backups, and bearing in mind the complexity of the backup system, I think I will just rely on it and not bother to delve any further.

Still, it is odd that my list of backups shows only full backups, despite Macrium being set to do 4 diff. backups as well:

 

[Norton]

Changing your settings to 1 full and 4 differential would be the way to set up your back ups.