Backup and Restore with Macrium Reflect  

A few days ago a fellow member wrote this about Macrium Reflect on another thread:

Stevekir said:

I have a file that I have set up to be backed up Full once per week, with 4 Differential backups during the week. The Full and the Diffs are set to be retained (I assume for that week). This obviously means that there will be a Full backup every week. But what about the 4 Differentials. I know what a Diff. is but I don't understand what Retaining 4 Diffs means.

He then asked several questions about differentials. I will quote my reply here, it just might help possible readers of this tutorial, too:

Kari said:

Stevekir said:

1. During the week there will be four Diffs made at equal intervals of 1.75 days (7/4 = 1.75).

No. You can set backups to be made monthly, weekly, every day, every specific week day or every X days where X is an integer (1, 2, 3 etc.). It can't be a fraction (1.75, 0.6, 2.5 etc.).

Stevekir said:

2. The first Diff. will record all the changes since the Full backup was made; the second will also record all the changes since the Full was made and so on.

Yes. A differential image backs up changes since last full backup, an incremental image changes since last full, differential or incremental backup.

Stevekir said:

3. At the end of a normal week the Full and the Diffs would be deleted and a new Full immediately created, with the new Diffs created in turn during that new week.

Let's call subsequent full backups as Full1, Full2, Full3 and so on, and respectively differential backups as Diff1, Diff2, Diff3 and so on.

You have a backup schedule to make a full backup once a week and a differential every second day. Retention rules are set to keep one full and four differentials.

According to your sample backup definition, Full1 will be deleted when Full2 will be created, Diff1 will be deleted when Diff5 will be created, and so on.

• Week 1, Day 1, a full backup Full1 will be made, followed by differentials Diff1 on Day 3, Diff2 on Day 5 and Diff3 on Day 7
• Week 2, Day 1 a new Full2 will be created and according to retention rules, Full1 will be deleted
• Diff1, Diff2 and Diff3 will now become obsolete and useless; they could no longer be used to restore Windows because to restore a differential image its parent full image is required
• Based on above, you should change retention rules so that a full backup is kept until its last child backup (differential or incremental) is deleted, in this example case if you only want to keep differentials for one week and you create a full every week, you should keep two full backups, deleting Full1 only when Full3 will be created and last child differential of Full1 will be deleted

Stevekir said:

4. If during the week a crash occured and the computer was re-booted, the last Diff created before the crash would be double-clicked on and the Full backup would be updated to the time/date of that last Diff.

No. Full image would not be updated. You just begin restore process selecting the last differential as image to be restored, it then uses its parent full image as base restoring it, then applying changes in itself.

Stevekir said:

5. That updated Full Backup could then be used to restore the computer to the position it was in when the last Diff.was created.

No. See above.

Stevekir said:

6. This is the reason for creating Diffs. and the only reason.

You create differential and incremental images because they will be made faster and will be smaller than full backups.

Kari

Pipppero2007 said:

Using the free edition so i dont have "Complete SSD trim support", and i have a ssd, there can be problems in a eventually restored image?

It's enough to have SATA in AHCI mode set in BIOS.