Deleting old Differential Backups

I have done a search of this forum and have gleaned what I believe to be correct. However, before I take any action, I would appreciate confirmation.

I have stored on my USB external HDD a full backup image of my laptop HDD. There are also 5 differential backup images, each getting a bit larger as they progress over time. It is my understanding I can delete all but the original full backup image and the most recent differential image and a recovery will still be available to the latest configuration should it be needed. Also is there any opinions/rule of thumb regarding how many differential images one would be well advised to maintain and how often to create a new one.

What is motivating this is my extenal HDD is getting near 3/4 of its capacity.

BTW... I'm using Acronis TI v10 build 4942 on XP Home SP3.

Thanks in advance... Raybro

 

The original full backup and the last differential will still be usable with all the intervening diffs deleted. However you will no longer be able to run a validation of the last diff if your wanted to restore to that point.
Perhaps it would be better to start over with a fresh base image. My own choice was to get a bigger backup drive and only now do full images....Less to worry about

Xpilot

 

Thanks for the response Xpilot... If you could clarify one point for this thick head I'm cursed with.

I run a validation of each image immediatly after it is created, so I do not normally select the validate image option available during the restore process. Is that what you are referring to?

Can I assume (and I believe you said) deleting the intervening diff images between the original full backup and the most recent diff image would NOT have any adverse effect on the restore process?

Thanks for your patience... Raybro

 

It's my understanding that any validation will not be able to be performed if you remove any inbetween differential backup files.

As long as the full and differential images used in the restore are valid, the restore should work normally. The only way to test it would be to do a restore since you couldn't run a separate validation.

---

If you want to remove some differentials to make some space and still want to be able to validate your new images, I would suggest you keep the last (most current) differential of the "old" set and rename it (keep track of the original name). Then create the next new differential off the full and it will be seen as the "first" in the set and validations can be performed normally.

 

Please note that any ATI validation only verifies that the files has the same content it had when it was written. This is not a comparison with the original data nor a test that the file was written correctly in the first place. This is good to know about a file but a validation doesn't tell you if ATI can restore your PC. To do that you need to go through the steps of doing a restore and see if it works. Short of that, you need to gor through the steps righ up through selecting the backup file and the target drive to be restored but not clicking onthe final proceed -- if you can get that far, then it's 99% certain you can do a successful restore. Not going at least that far leaves you open to several potential issues, the most common of which are ATI unable to see the drive with the backup, ATI can see the drive to be restored when selecting the backup-file drive but can't see it when you try to select the drive to be restored, and ATI unable to correctly read your USB drive. These problems arise during an attempted restore mainly because, like most backup-image programs, ATI restoration uses linux and might not have the right drivers to work on your machine.

 

Now, that's just plain clever. I wish I'd thought of that. So simple and obvious - after you've seen it.

 

I'm one of those that likes to validate images. This way you still have access to the original by renaming it back (after moving or renaming the "new" differentials) and you can also have validations on new images.

 

Thanks to all for their responses. The net effect is to have given me a better understanding of how one can use the Acronis TI program.

I did, in fact, do a restore using an original backup and diff image #5 and it worked just fine. Prior to doing so, I attempted to run a validation of the diff #5 (after I moved #2 thru #4 to a seperate folder) and it would not complete the validation process. So I made a new full backup, then ran the restore using the old original and diff #5 an it worked just as it should. One can really get lost in this, but so far so good. Again, thanks to all.

Raybro