Hi Joshua
I also don't think that scrubbing along corrupts anything, it is obviously there to stop corruption between raid disks... BUT, I do think that if time Machine trys to backup while the freenass is scrubbing, it then causes the corruption.
That is why I want to know if It can be disabled.
I setup my first FreeNas about a month ago now, and I have had to do a complete time machine backup 3 times now - once for the first backup, and twice because I have been getting the error message "Time Machine completed a verification of your backups".
I found this very helpful thread:
https://discussions.apple.com/thread/3658856?start=45&tstart=0 and the important part:
"After the last "poof" I really started digging and found something interesting. I was always puzzled at the periodicity of the problem (always Monday mornings). I discovered that my NAS upon which the TM server is hosted runs a weekly RAID scrub starting at 4AM, which runs until around 11AM. The TM failure always occurred in this time frame - around 8-9 AM. For those of you new to this thread, TM was invalidating my backup history every week or two, on a Monday, and recreating a backup. This problem started with Lion - it never existed before. Something about Lion is less accurate when it comes to verification of writing, so the data is being corrupted when the NAS is busy scrubbing the RAID.
I decided this must be the process which is the proximate cause (the main problem being some change in Lion's writing of the data). But how to fix it? TM backs up very often, so it won't do to just change when the RAID scrub occurs. I found myself wishing there were a feature in TM that would let me "window" the backup schedule to avoid the RAID scrub time frame. So I did some searching and found "TimeMachineEditor", a free utility that lets you build complex schedules to run TM. I was not only able to window the TM process to avoid the RAID scrub, but I was also able to set TM to run hourly rather than every five minutes.
So far this has worked. I anticipate that this will solve my problem. I will of course keep you all posted.
Thanks for your time,
H."