Looking for Recommendations for backing-up one Drobo to another Offsite

I have a 2T iMac in my house being backed up directly by Time Machine to a Drobo S containing two Hitachi 2T and one Seagate 1T hard drives. All are 7200 RPM drives. I am connected via ethernet to the office in my workshop about 250’ away. There I have an older Mac Pro connected directly to a second generation Drobo containing the same number and type of hard drives as in the house. The iMac is running Snow Leopard (10.6.2) and the Mac Pro is running Leopard (10.5.8.) I want to back-up the house Drobo S to the Drobo in the workshop to provide redundant and off-site back-up. I am looking for suggestions regarding what software and procedure to use in accomplishing this.

Since they’re already networked together on the LAN, you could just use Drobo Copy (part of Drobo Dashboard). I guess it depends on how sophisticated your backup strategy is.

There are a couple of options I would look at

  1. rsync
    This utility is included with OS X but it is a command-line utility that you run from the terminal. rsync has a lot of features but the most notable is that it synchronizes your backup copy by only sending the differences over the network rather than whole files. Greatly speeds up your backup. You can configure a job to run this automatically.

I would setup an rsync server on the Mac in the workshop. Then I would write a script on the Home Mac that initiates the backup which could be scheduled to run automatically.

  1. File Copy over network shares
    This would involve setting up file sharing on the Mac in the workshop to share out space on the Drobo. The Home Mac would then connect to the workshop Mac as a network drive.
    You then have a couple of options
  • use DroboCopy to automatically copy files to the network share
  • use free utility arRsync to copy files to the network share (an easy to use GUI to the rsync utility i mentioned above that works for local file copies).

This option will be slightly slower. It will only copy across files that have changed, but it will transfer whole files rather than parts.