The Backup submenu allows you to perform a backup of a selected device or MBR. There are several supported backup types.
So open Spacefm as root, be sure that Show internal partitions is checked in the directory tree and right click on a partition (be sure it is unmounted), Root, Backup, choose FSArchiver, select the place you want to save the backup file and go.
FSArchiver (website) is a modern program which creates an archive of a filesystem. It is similar to tar, except that the archive includes checksums, can be restored if corrupted, and includes additional information.
One disadvantage to using FSArchiver is that unlike Partimage, the on disk locations of files will change when restored. For most files this won't matter, but in the case of grub's stage files, moving them can cause the grub boot process to no longer work. Thus if you restore a volume containing grub's files using an FSArchiver archive, you will then need to reinstall grub to the MBR (so that it knows accurately where it's files are - these locations are stored in the MBR's boot code).An advantage to FSArchiver is that it supports more filesystem types than Partimage, including ext4 and btrfs, and several compression methods. Other advantages include file exclusion, multi-thread compression, and encryption. The data may also be restored to any partition large enough to hold it, regardless of the original partition's size. FSArchiver is also currently maintained,
To restore using spacefm, right click on the partition to be restored and choose restore from file. Or in terminal:
More info: http://en.wikibooks.org/wiki/How_To_Backup_Operating_Systems
Restore Partition - FSArchiver Method
If you created your backup file using FSArchiver, you must use this method to restore it.
WARNING: All the data currently stored on this partition will be overwritten!
Working by example, to restore /dev/sda5 from the backup file /mnt/back/backup-sda5.fsa (substitute the device name you wish to restore to!):fsarchiver restfs /mnt/back/backup-sda5.fsa id=0,dest=/dev/sda5