Image size differs from actual boot size
I've just used AOMEI Backupper to backup my windows 8.1 boot drive partition for the first time.
I chose the option "disk backup" and set the compression to 'none', and the file appeared to backup succesfully.
However, I noticed that the image file was substantially smaller than the space used on the boot partition. I mounted the image file as a virtual drive and this confirms that suspicion.
The actual boot is 21.1 GB
The mounted boot image is 18.1 GB
Can anybody please explain why this is?
Thank you
- Michael
p.s this program seems amazing, especially for a freeby. Good work people, I appreciate it.
Comments
It also ignores the hybernation file if present. Another potential difference is one has a representation of a file system while the other is actually a file system. For the real file system, data is stored in packets that are called clusters. When a file system is created, a cluster is the smallest addressable unit of data. NTFS, the most commonly used file system with Windows 7 and 8, the default size is 4 KB. This means that for all files 4 KB and smaller, they take up a single cluster. When you have 1000 files that are this size or smaller, you still take up 4 KB * 1000 disk space. If your files range in size from a few bytes up to 4 KB, your uncompressed image archive will only be as large as the actual data that was backed up. I realize this is an older topic, but I figured it wouldn't hurt to expand on the answer.