I need to keep offsite copies of my zimbra full and incremental backups with no time limitation.

For now, I use a cronjob every night calling a script :

/usr/bin/rsync -aHvz myzimbra.mycompany.com:/opt/zimbra/backup /local/dir/

It does work but it's eating my disk space, as each new full backup takes 18 GB instead of less than 2 on the server.

It's not keeping the hardlinks. I was thinking about use the --link-dest option of rsync, and filter on full backups only, but the "small full backups" (made when you create a new account) kill this solution.

So, anyone have experience with offsite copies of /opt/zimbra/backup ?