Easiest RAID configuration to recover data if ReadyNAS fails

Earlier today, when I woke up, the rebuilding process restarted (it was at more than 50% when I went to sleep). The only new entries on the logs (that you can see on the web interface - I didn't look at the log files) were snapshot entries. I assume those triggered the restart of the rebuilding process. I'm not sure, however, because there were 10 hours between the log entries and the time I saw the rebuilding at 0.xy%, and that's very odd. I've sent the new log files to the support staff and am waiting now. I've also changed the snapshot interval from daily to weekly on all shares.

I'm a bit worried about all this. I want to try and backup my data, but I guess I can't remove one hdd while it's rebuilding. I am also wary of simply copying what I can to my computer, since I would be accessing hdds a lot and that would at the minimum slow the rebuilding process.