@telent
Cron job,
tar cvf - [directories] | ssh user@host 'cat > backup.tgz'
My first UN*X machine had 1Mb (not Gb) of core, and 40Mb of disk. You don't need anything complex to do net backup..
@simon_brooke yes, I do rather suspect I'm overcomplicating things. Probably just install rsync on it and call it quits
@telent there's also duplicati, but that needs mono so I don't know if it's ideal for that low RAM