Size difference between an incremental backup and a differential
I created a full backup, then several diffs over the next few days.
The differential backups were about 4 gig each.
Then I switched the backup method to Incremental and ran it.
The incremental that was generated was 30 gig.
I would expect the incremental to be no larger than the largest differential.
I certainly would not expect it to be almost 10x larger.
I then switched back to differential and ran it. That differential file was back into the 4 gig range.
Why would the incremental be so much larger than the largest differential?
All of these backups were done within a day or two of each other and nothing was installed or changed on the machine.
I would concur with user Nils. The changes you describe made to one task will make the subsequent backups useless.
As you found out, there is no way of knowing what is included within the backup now.
If changes needed, my suggestion is to stop using the old task and create a new task with the correct settings.
If you wish to compare the two methods, create an indivudal rask for each type.
An incrmental includes disk sector changes since the last backup. The data inside the incremental is not included in any future backup.
A differeential includes disk sector changes since the last full. The data inside the differential will be included in future backps as the differential is all changes in disk sectors since the last full.
Each differential will be progressively larger.
Each incremental will only have the disk sector changes that have occurred after the last incremental was run.
When restoring an incremental, ALL PRIOR incremental must be present in order for the restore to complete.
When restoring a differential, only the full plus any single differential are required for the restore to complete.
Note: running defrag anytime after a full will cause the next inc or diff to be larger than expected due to all the changed disk sectors.
These are the steps which I use to make the program work successfully for me.
1. For each new version, I remove the old. run a cleanup utility. Cleanup the residue and install into a fresh new install.
I don't try to carry old tasks into a new installation.
2. I create all new tasks and do not later modify. If changes needed, I stop using the old task and create a new task.
Each task name is different so no duplication or confusion for the program.
3. Each of my tasks is set up for automatic cleanup so manual deletion of old backups not needed;
or I use manual backups (someimes even backups via CD) with manual deletions.
4. Added later. If a backup is restored, I stop using the restored tasks and create new tasks after the restore.
5. My tasks work based on the above.