Windows 10: Question about Macrium Reflect Differential Backup

Hi. Macrium Reflect free allows 4 differential backups per full backup. If I have a full backup and 1 differential backup and I want to make a second differential backup, does it matter if I make it from the 1st differential backup or from the full backup? Thanks in advance for any replies. Running Windows version1909.
Mark

:)

 

Question on Macrium backups

Short answer:

This is not about archive bit, it's all about a backup plan; if the Sunday and Wednesday full backups belong to same backup set, a differential image when restored restores the last full backup regardless if it's your Sunday full or Wednesday full, then the last differential backup.

In other words, archive bit has nothing to do with Macrium Reflect backup.

If your Wednesday full backup files have a different backup definition (the 16 character hexadecimal part of the filename) than your Sunday full / every other day differential set, then it's exactly as it should be. The Wednesday full will not be used when the original plan's differential will be restored.

Somewhat longer answer:

Let's say that you created a full backup now on Sunday, today Tuesday a differential, tomorrow Wednesday again a full backup, on Thursday a differential and so on.

If you now restore the differential made on Tuesday, it restores itself and full from Sunday. If you restore the Thursday differential, it picks up besides itself the full from Wednesday. This is not because Wednesday full backup cleared the archive bit, it is because both Sunday and Wednesday full backups belong to the same backup plan.

A backup set is a set of full, differential and incremental backups. When you created your first backup with Macrium Reflect you were asked to name that backup set (backup plan):





The file names of each backup file in each backup set have the same hexadecimal string as filename, followed by digits. Below an extract from Macrium Reflect tutorial here at Ten Forums, its Part Four Step 8:

What you want to achieve is simply done by creating a new backup plan for your Wednesday full backup. This puts the Wednesday full backups to a new backup set, without any whatsoever connection to your other backup set. Macrium Reflect is an intelligent application, by default it assumes you want to create a new plan and prompts for the name:





If you now give a new plan name, the backup will belong to new backup set with a different filename. To include this backup to your existing backup set you would need to browse and select the name of that set.

How backup sets are created and maintained - KnowledgeBase - Macrium Reflect Knowledgebase

I might have misunderstood the highlighted part in above quote, but just to be sure I want to add this:

You don't have to restore first the last full image and then the last differential image. Simply restore the last differential image, it will automatically restore last full it finds belonging to same set, thereafter itself.

Restoring first a full image is completely unnecessary.

 

Restoring Windows 10 Image using Macrium Reflect


In addition to the above. Here's my suggestion in step by step.
I assume you have Macrium Installed in your current HD and already made a backup copy.

1. Connect your new HD via USB port and boot up.
2. Run Macrium, click on Restore tab then select the Backup Image that you made to restore
3. click on "select a different target disk" then select your new HD as destination
   
   
   
4. Proceed to restore then Shutdown and disconnect the old HD and replace with the new HD
5. Boot up with your new HD.

 

Differential Backup Size vs. Full Backup Size


My backup process is to manually do a full system backup followed by periodic differential backups until the size of the differential backup gets too big. My question is how big is too big? My thinking (and this is just a guess) is that when the differential backup is about 25% the size of the full backup, then it’s time for a new full backup. But again that’s just a guess. Is there an optimal percentage? I use the free version of Macrium Reflect 7.1 on a Windows 10 (1703) 64-bit Home PC.