In Linux/UNIX, you can always 'cd' to an absolute directory, as you show in your example in /var/cache
Not being an rsnapshot user, I don't know the ins and outs of it, but I'd guess it's a command line utility where you specify the source and destination directories and then just let it run.
From what I've seen on the rsnapshot website, it's a bit more basic than NetApp's snapshot utility. Snapshot is configured to run hourly, daily, and weekly backups, and retain the last two backups of each. rsnapshot makes no distinction as to what the increment is, so it's not as smart:
NetApp Weekly knows to backup all changes since the last weekly. Same goes for Daily and Hourly. Rsnapshot just backs up all changes since the last backup, regardless of how long it's been since the last one.
The difference is that rsnapshot will take up more space since it incrementally saves all changes as you go along with no option to delete any midterm backups.
Given how inexpensive storage is, it's still a nifty utility. It's kind of like Apple's upcoming Time Machine where it'll let you go back to any scheduled point in time since the full backup to recover a file.