System Image Backup is smaller than Bare C Drive

[quantumtheory]

I am running Windows 7 Home Premium 64 bit. I recently used "Create System Image" for the first time right after a fresh install on a formated hard drive. During the backup, it stated that the backup would take close to 23 GB. I chose to back up the image to my second hard drive. It completed successfully (so it said). I then checked the size of the image backup and it was only 12 GB. Did it indeed, backup the image successfully? Will I have a problem recovering the image, when that time comes along? Why the compression? Will this affect the performance of the recovered image?

 

[Wishmaster]

Most Imaging apps compress the DATA they are backing up. How much compresses it depends on the Application, and its settings if they are configuarble.

This is normal.

 

[mjf]

Even with Windows imaging I think it's a fairly simple estimate of what actually gets included in the image. If the image was successful it should return you to an accurate operational state.

You can always mount your windows image and explore it's contents using this tutorial:
http://www.sevenforums.com/tutorials/24771-system-image-extract-files-using-disk-management.html
Macrium Reflect images are even easier to mount and inspect.

 

[kado897]

The image is compressed plus I don't think it backs up your Pagefile or Hiberfile.

 

[quantumtheory]

Thanks for the quick replies, guys. I didnt know it was compressed. I thought the reason they say "this backup could take 23 GB" was because you actually needed that space to save the backup.

 

[Barman58]

I believe the "could take" figure is a worst case figure - this provides you with the minimum free space required for the backup device - actual space used depends on the nature of the data and should always be less than the "estimate"

 

[GeneO]

The image is compressed plus I don't think it backs up your Pagefile or Hiberfile.

Or your shadow storage (system restore)

 

[kado897]

The image is compressed plus I don't think it backs up your Pagefile or Hiberfile.

Or your shadow storage (system restore)

Thanks. I missed that one.

 

[karlsnooks]

The "image" format is .wim, Windows Image.

This is not a compressed format, however, as others have mentioned, superfluous data is not included.

As also mentioned, this wim file can be mounted and viewed via Disk Management.

If you perform a date backup of perhaps the Documents library, then you will see that Win 7 Backup and Restore has generated .ZIP files. which are compressed files.

The Win 7 terminology can lead to confusion and, as mentioned, the figure shown by Backup and Restore as to the amount of space needed is a worst-case scenario. I've never managed to come close to the number they show.

 

[kado897]

The "image" format is .wim, Windows Image.

This is not a compressed format, however, as others have mentioned, superfluous data is not included.

As also mentioned, this wim file can be mounted and viewed via Disk Management.

If you perform a date backup of perhaps the Documents library, then you will see that Win 7 Backup and Restore has generated .ZIP files. which are compressed files.

The Win 7 terminology can lead to confusion and, as mentioned, the figure shown by Backup and Restore as to the amount of space needed is a worst-case scenario. I've never managed to come close to the number they show.

Actually the format is vhd

 

[karlsnooks]

My mistake. I've looked at enough of them. Guess I'm just too accustomed to putting wims on a virtual hard drive and using DISM to mount,modify,unmount wims.

.

 

[kado897]

No problem. I think you may be right about not being compressed however.

 

[mjf]

The "image" format is .wim, Windows Image.

This is not a compressed format, however, as others have mentioned, superfluous data is not included.

As also mentioned, this wim file can be mounted and viewed via Disk Management.

If you perform a date backup of perhaps the Documents library, then you will see that Win 7 Backup and Restore has generated .ZIP files. which are compressed files.

The Win 7 terminology can lead to confusion and, as mentioned, the figure shown by Backup and Restore as to the amount of space needed is a worst-case scenario. I've never managed to come close to the number they show.

Actually the format is vhd

View attachment 160153

Yes indeed

 

[quantumtheory]

Well, thank you all for the great help in putting my confusion to rest. I've learned quite a bit just from this one thread. I can't wait to learn more from this forum.

 

[kado897]

You are welcome quantumtheory. There is a lot of useful information here.

 

[karlsnooks]

Well, thank you all for the great help in putting my confusion to rest. I've learned quite a bit just from this one thread. I can't wait to learn more from this forum.

Happy Grazing.

 

[Majestic One]

My first post here @ se7en forums & am proud to be a member of THE foremost leader in Windows 7 solutions to serious windows problematic issues. I have gotten light-years of help from this forum, so much so, my eye is looking for www.sevenforums.com when i am looking for a solution. So today, I decided why not give back to a community that has helped me so much. Today I am a Se7en Forums member for life.

Thank you. And with that being said...

I was concerned also when my DVD backup was 3 DVD's vs. the expected 8. Googling "Superfluous" (lol) and reading this forum thread it all makes perfect sense. Thank you to those with your input on this matter. (sure hope it works! - anyone know how to test it besides actually restoring the image?)

PEACE!!!

-Chris

 

[whs]

I think there may be a little confusion regarding compression. If the image does not store e.g. your pagefile or your hiberfile in full length, it still knows that it is there and what the size and location of it is. It just make a descriptor record defining the location, length, etc. Then upon restoration it can 'revive' those files.

The same happens with large areas of blanks. The image keeps track of them but does not map them one by one. I would call this technique compression. What do you call it.

Not certain about Windows imaging, but a Macrium image turns out to be about 60% of the used part of an OS partition and more like 80%+ for a data partition (because there is less opportunity to compress).

 

[kado897]

I think there may be a little confusion regarding compression. If the image does not store e.g. your pagefile or your hiberfile in full length, it still knows that it is there and what the size and location of it is. It just make a descriptor record defining the location, length, etc. Then upon restoration it can 'revive' those files.

The same happens with large areas of blanks. The image keeps track of them but does not map them one by one. I would call this technique compression. What do you call it.

It was my understanding that this is achieved when you specify "Intelligent Sector Copying" and that compression was applied to the image after that.

 

[whs]

I am not sure Keith. I do not recall to ever checking "Intelligent Sector Copying". But maybe it is default.