Can the restored file-system be a boot filesystem (like the root partition) ?

Yes, FSArchiver can backup the root file-system, but you may have to run grub-installer again after you restore the file-system where the boot-loader (grub) is installed. FSArchiver has been successfully able to save and restore the root file-system of a Fedora-8 with SELinux on it as you can see in the status page.

When I save the root file system, and restore it as another file-system, is the fstab modified ?

FSArchiver is working at the file-system, it’s not supposed to know anything about the contents of the file-system. It’s just supposed to preserve the files/directories and their attributes, and the human has to think about the changes required to get it to work (support for file-system in the kernel, fstab, …). FSArchiver also aims to preserve the important file-system attributes, such as the file-system label / UUID. We assume the system administrator knows what he is doing, and fixing the fstab is trivial, so the administrator will just have to edit fsatb before he reboots. You can also set the file-system as auto in fstab so that it can boot on any file-system.

What file-systems are currently supported ?

FSArchiver is able to save/restore all linux file-systems (ext2, ext3, ext4, reiserfs, reiser4, xfs, jfs, btrfs) as well as ntfs (fat is not supported). The specific file-system attributes are supported for all these file-systems. It means that both the data (file contents, file attributes except acl) and file-system attributes (label, uuid, block size) are preserved as well as several advanced file-system attributes such as inode-size on ext{2,3,4}. Anyway, several advanced file-systems attributes still need to be implemented, such as the journal attributes for ext{2,3,4}.