System Image Backup is smaller than Bare C Drive

quantumtheory · 15 Jun 2011

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 · 15 Jun 2011

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 · 15 Jun 2011

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:
System Image - Extract Files Using Disk Management
Macrium Reflect images are even easier to mount and inspect.

kado897 · 16 Jun 2011

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

quantumtheory · 16 Jun 2011

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 · 16 Jun 2011

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 · 16 Jun 2011

kado897 said:

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

Or your shadow storage (system restore)

kado897 · 17 Jun 2011

GeneO said:

kado897 said:

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 · 17 Jun 2011

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 · 17 Jun 2011

karlsnooks said:

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