What you gain from crashplan that you don't get with AFP backup is deduplication(space efficiency), automated backup, encryption, compression, version control. Just using freeNAS features you can get compression and version's but it's not in a nice little package like crashplan provides.
Guess I wasn't clear.
I ran CrashPlan on the iMac. The CrashPlan Destination was FreeNAS mounted as an AFP Share.
If you are looking to just backup a single computer to your FreeNAS maybe crashplan is a little to complicated and I say with the idea that there could be a much simpler way to do it if you don't need all the crashplan features. Since you have a Mac did you evaluate just using time machine over AFP? I think this works on freenas, I have seen people complaining but I don't own a mac so haven't paid much attention to it.
I had two goals.
First, I wanted to backup multiple computers, my own and extended family members.
As I recall, when first did this, FreeNAS allowed only one AFP to be designated as a Time Machine (TM) destination. And, as I recall, I needed to have a separate FreeNAS user for each computer, otherwise the TM files would become commingled. In other words, if I someone in the family decided they no longer wanted to use my service, I couldn't delete their files unless they had their own username. There was also a problem with quotas. TM doesn't support quotas so unless each person has their own FreeNAS quota-enabled Dataset, they could end up hogging space from other users. It was a long time ago, and I may not have the specifics correct. Nevertheless, I managed to cobble together a Rube Goldberg configuration that seemed scalable and maintainable (for my needs).
Then came the testing and I found that it just wasn't stable. Every few weeks TM reported that it could no longer work with the existing dataset and had to start over with a new initial backup, discarding all the history of incremental changes until then. The third time this happened, I decided that I just didn't trust TM with my backups.
My second goal was to support remote backups.
Several people told me that opening my network firewall to AFP traffic for TM was a bad idea. This was the final nail in TM's coffin. I mean think about it. What good is an automated backup unless it works automatically as you travel? Yes, I could have fiddled with a VPN or SSH connection to my network and run TM over a secure connection. But that's not exactly automatic. Not to mention, I was trying to provide a service for my mother. I really didn't want to mess with VPN or SSH on her computer.
The bottom line is that TM is a single-user solution for people who are willing to take their backup drives with them as they travel. Kind of dumb to travel with both your original and backup disks. But, it's dead simple. And it's better than nothing. Best of all, the Apple Store supports it and they'll help you with the restore. Several extended family members continue to use TM instead of my CrashPlan service on FreeNAS.
