Acronis TI image only 766 MB !!!

Normally my Acronis images are about 1.5 to 2.0 GB. Today, I zero-filled my C partition and then reinstalled XP Pro (plus all the normal programs). I then did an image with ATI and it was only 766 MB! I couldn't believe it. Clearly zero-filling must have a huge effect on the size of the image. How is this possible?

 

If I correctly remember a fresh XP SP2 pro installation takes less than 1.5GB
In case you enabled compression, this decrases the size about twice - so 760MB seems normal, not sure if zero-filling is related at all.

 

What do you mean by "all the normal programs"? Did you install any of your applications?

 

My image of XP PRO with SP2 is .99 gigs (just XP PRO without any updates and no applications).

 

Yes, I installed all the same programs that I always do. This is XP Pro SP2 with all the updates and all the programs--total size on disk=3.0 GB. The image I used to get was 1.5 GB. The only time that I zero-filled the C partition I get 766 MB.

 

Mount the backup and visually check to see if anything obvious is missing.

 

I actually restored the image and everything is fine. I'm not concerned that the image is small (happy), just want to know why it is so small when it never was before.

 

Interesting!

I wonder if doing a zero fill made the compression a lot more efficient since it would put in the code to say the next many, many bytes are zeros rather than having to put in the codes for random garbage.

 

When the pre-fetch and temporary files starts building up the Image will get bigger in size.

 

Well the absolute test is to restore the image. If I were doing it, I'd remove your boot disk and restore it to another disk. That's just too small for SP2 with updates and programs added.

Is there any possibility that you did a Files and Folders backup instead of a disk image?

 

Very interesting indeed. When I get back home I might just test this out. It's going to be a couple weeks though. And this was Normal compression? That's quite a reduction - about 75% reduced.

 

Sounds too small, but it isn't. I did restore the image as a test--used the recovery CD. Everything's there. No, I did a complete partition image. Remember this is just restoring a partition image, not the whole hard drive.

 

Just for fun I mounted two images--one is an XP Pro 1.36 GB image and the other is the XP Pro 766 MB image--both are essentially the same--3.0 GB on disk. The only difference is that the larger image has a Config.Msi folder (protected operating system file) and the smaller image does not. Everything else is identical.

 

That sounds like a plausible theory. In an XP installation that's been in use for a while, each cluster may still contain random garbage bytes past the end of the file to the end of the cluster. If there are enough partially-filled clusters on the disk then I would assume TI would just copy all of the data in each in-use cluster to the image, including the garbage bytes. If the ends of each cluster were zero-filled, then perhaps the compression algorithm works more efficiently.

Weren't there utilities available to zero the unused tail ends of clusters? If someone knows of such a utility then they could try a test to prove/disprove this theory.

 

Hello ltsnow,

Thank you for choosing Acronis Disk Backup Software.

Please notice that the Config.Msi folder is used by Windows Installer application to store temporarily data, and it's not always cleared, so it may be quite large. Please also note that files in the Recycle Bin are not actually deleted, so they get backed up as well and can add to image size.

If you have any further questions concerning Acronis software, please feel free to submit a request for technical support or post any of them on this forum. We will certainly try to help you in resolving any issues.

Thank you.
--
Marat Setdikov

 

There could also be gigabytes of data stored in "C:\System Volume Information" as part of System Restore. Wiping the disk and re-installing XP from scratch would clear all that out.