Storage Disk Compression

I am getting my backup system up and running and presently in shakedown mode. But for one thing I am just a bit puzzled about how backups are stored compression wise.

As I understand it files should not be compressed but images are. However my file backups are definitely compressed in some way because the size of my very first full backups of any computer on my system are approximately 60% of the original. These are being saved to a dedicated hard drive under NTFS and it is not set up with Windows compression enabled.

Also, I would like to make a safety copy of the backup files on another drive. Somewhere I saw comment about a server feature to be able to create a copy of all the backup files - is there such a feature? If not, I am happy to just make a copy so I can at least manually access the files involved.

And in getting back to my first question - this process of making a safety copy is where I picked up that my file backups were compressed in some way. Because the copy I made (using Syncback) ended up approx 1.8 times the storage size!!! I am now in the process of applying Windows NTFS compression to that drive to reduce it’s size!

I think the size difference is down to the deduplication where duplicate files are sym-linked to a single instance. Something Microsoft also do extensively in the WinSxS folder which absolutely balloons in size if you try copying it…
The presence of (many) symlinks makes a simple file copy to a second location problematic weird stuff happens, as you found out.

Best bet might be to image the drive, or better the entire UrBackup server, either using another instance with the server as its only client, or some other program eg Macrium Reflect, that way you get an accurate snapshot of both the storage and the server in a consistent state provided the whole thing is snapshotted together. Since that’s done at the block level rather than file level… things behave as expected.

You can mount the image if you need access to individual files.

Other people may have other suggestions, but that’s my 2 pennyworth on the subject.