>>> And if I pull, none of my backed-up systems are secure because anyone >>> who breaks into the backup server has root read privileges on every >>> backed-up system and will thereby "gain full root privileges quickly." >> >> IMO that depends on whether you also backup the authentication-related >> files or not. Exclude them from backup, ensure different root passwords >> for all boxes, and now you can limit the infiltration. > > If you're pulling to the backup server, that backup server has to be > able to log in to and read all files on the other servers. Including > e.g. your swap partition and device files.
What if I have each system save a copy of everything to be backed up from its own filesystem in a separate directory and change the ownership of everything in that directory so it can be read by an unprivileged backup user? Then I could have the backup server pull that copy from each system without giving it root access to each system. Can I somehow have the correct ownerships for the backup saved in a separate file for use during a restore? - Grant