For folks that want to back up data on remote servers, BackupPC is one of very few comprehensive backup systems I've found that can run on a server hidden in a closet somewhere and connect out to the remotes to retrieve data. Most backup systems run on the remotes and have the remotes connect into the backup server in some fashion, which I find kinda horrifying.
I've used BackupPC for a long time and I totally love it, though I get why it's never been the most popular option. The initial setup will take an experienced sysadmin a couple of hours if they're doing it for the first time.
This is pretty straightforward to do with standard rsync. You just setup a ssh tunnel first and have it use that. That's how I backup my VPS from my home fileserver.
I've used BackupPC for a long time and I totally love it, though I get why it's never been the most popular option. The initial setup will take an experienced sysadmin a couple of hours if they're doing it for the first time.