How do I back up a large capacity drive to a smaller capacity drive when the larger drive is running low on space?

Question

System administration

There is a 1TB hard drive. on the server computer. It is required to make a backup copy of the data that is loaded in case of death of the original. The problem is this - there are smaller hard drives (500 GB or less), while on the original hard drive the space is occupied by 60 GB, which seems to be possible to transfer to a very small hard drive. The question is:
1. How to transfer? There is a USB adapter for connecting 2.5 "-3.5" drives, can it be connected through it, or is it better directly to the motherboard?
2. How to transfer? I draw your attention again, we need a program that will allow you to transfer not a complete copy, but only the files themselves, and so that later, in the event of a breakdown, you can replace the hard disk with its copy.
3. A general theoretical question - what is the name of the method of backing up OS files when not a sector-by-sector copy is created, but the data itself with the ability to boot (copying the boot sector, of course right there).

Answer 1

Disk manufacturers and developers of specialized software have agreed and for almost every new disk you can legally get a copy of the program for transferring (reserving, splitting, aligning, etc.) data. Acronis TrueImage or Disk Director (and maybe BackUp & Restore), Paragon Hard Disk Manager. Or just go to their websites and choose the free or trial edition. You don’t even need to pirate, for the sake of one or two times.
Moreover, the transfer is not even of files, but of the table itself, but the empty space is truncated accordingly, for example, "Clone with resize".
The axis is not important, there are "native" boot disks (although they need to be made, but the tools are included in the programs) based on Linux, WinPE, or use options with third-party Live images.

Answer 2

1. Drive Snapshot (there are modes for excluding folders from backup, work without insall and run on a live / saved OS, etc.)
2. MirrorFolder - here, only folders and files (without HDD sectors), for that, there are soft RAID1 (i.e. backup immediately in REAL-TIME mode!).

Answer 3

Why back up the OS? Backup only your data.
OS can always be rolled. Or prepare a second disk for booting (install the OS on it, configure it as it should, or clone the original boot disk once).
Then connect this disk as the second one and copy only your data to it, in any way possible, even with a self-written script from the scheduler.

Answer 4

Fill the void with zeros (sdelete / z) and drive it into qcow2 or even into bzip;

Answer 5

create the same partitions with the same
boot copy via dd and the boot area also
copy the data partition itself with the same rights

Answer 6

You can connect a screw to a linux machine, you can use the gparted graphical shell to remove free disk space - we make it as an unallocated volume, after that we make an image from the disk and you will have an image for uploading to smaller disks.