It seems that my honeymoon period with DroboSync was short lived. As you may have read I installed the new firmware and Dashboard then switched DroboSync on. It started immediately and spent the next 4 days copying data. I kept adding 2TB drives as the DroboPro-FS filled up. Yesterday I went to check on it, expecting it to be around 7TB full and I was surprised to see that the drive was now showing completely empty in Dashboard, just 234MB of its own system storage used. There was no data being synced yet the dashboard showed no errors for any of my DroboPros, all discs were good and the target and source were still selected correctly. Everything looked fine except all my data on the target had gone. Silently, in the night, with no warning.
I decided to recycle the DroboSync status. I unselected Target on the one drive. When I checked OK it said unable to save settings. In fact I could make no changes at all to the DroboProFS. The dashboard was still attached to it. In the end I did a full re-set. The drive came on line but now complained that it had the same name as another DroboPro FS (which it had as it had re-set its name - I had FS and FS2). I input the new name but it would not let me save the settings again. The only way out of this was to rename the other unit as DroboPro-FS1 then do a second reset on the Target unit. This worked but I was now screwed up as applications paths no longer worked.
I have now got my units back on line with DroboSync firmly off. It would take a lot for me to trust this again. If it can fail in such a way with a brand new unit, brand new drives on an unloaded switch it is of no use to me.