I currently have a NAS with a 2x2TB HDD 1x16GB SSD layout on a mini-itx atom board. The NAS is in a Lian Li PC-Q07 case. On this system I was running freebsd 8 with a gmirror raid 1 setup, which was enough for my needs.

So far I was using the NAS for:

• Fileserver with AFP protocol (only mac clients used)
• SVN server hosting all my source trees of my projects
• JIRA (performance was okay-ish)
• Timemachine backup for the macs

The power consumption was about 38W, although I did not put HDDs asleep when unused (I think this is not possible in a raid setup).

I liked the NAS because:

• the performance was good through gigabit LAN (enough for my needs)
• power consumption was good
• its a pretty small case and fits in one of my cupboards

I disliked the NAS a bit because:

• it was a bit noisy, the Q07 case vibrated a good amount because of the HDDs. I switched the NAS off every evening
• I do not have a real backup of the data on the NAS, only the internal raid 1 as safety. I really dont want to loose my source trees under no circumstances, so I would really be sleeping better if I knew I had regular backups somewhere.

Recently, the board seemed to have died, I can't boot anymore. Thus, I was thinking about a redesign of my NAS (I still have to find out what parts are broken, I probably need to replace the mainboard and SSD. HDDs seem to be okay).

First of all, I was wondering what other users have as backup for their NAS? Are you actually using a second NAS, and regularly copying over the data to have it safe? Or is there any better solution to this? I was thinking about getting a cheap NAS like the synology DS112j with only one disk, and use rsync or something similar to regularly copy data over to the second NAS (wake the second NAS upon start, shut it down after copy). Although this approach seems somewhat weird, It would have the benefit (?) that I could use a single disk instead of raid in the main NAS, and put the disk asleep when idle, and have the NAS running 24/7 with low energy consumption (I found no way to do this with a gmirror setup).
Is there any recommended backup solution for a small NAS?

Then I was thinking about a different raid setup. Since I have to buy a new mainboard as well as SSD, I might as well switch over to a i3 board with more ram, and also switch to ZFS. I am not familar with ZFS, I've never used it, but I read and hear much about it. Would it be viable to set up a ZFS storage with only 2 disks? Can I easily extend this storage with more disks, once I choose to add some? I could maybe get a new case like the Fractal Design Array R2 which has more 3,5" slots. I could as well get another 2 disks, but I would prefer sticking with the existing 2 for enegery/heat/noise reasons. Should I go for a ZFS storage or stick to my gmirror setup?

I would also like to keep freebsd as operating system, and also I dont need any web gui or something (that is, I dont need/want to use FreeNAS or Openfiler etc).

Does anyone maybe have a sample setup in use so I can compare energy consumption/noise/software setup? Any guidance towards the NAS of my dreams (silent, low energy, safe w/ backups) much appreciated.