I don't really understand the diferences between raid6 and raid10. I know they are both a good technical choice but which one is the best and why ?
RAID 6 is a way to provide extra redundancy ... it safeguards data against the loss of two drives within a short-ish time interval, whereas RAID 5 and RAID 10 do not.
However ... what you should be doing is looking at all the potential causes of data loss, with the frequency of occurrence. And you should be protecting against the various causes in order of frequency of occurrence while taking into account cost.
So you look at RAID 6 *after* you have covered off the more common causes of data loss, unless choosing RAID 6 is so cheap (in terms of performace as well as cash) that it makes sense to use it even though you are still exposed to more common problems than loss of two drives within a short period.
RAID 10 is simply a combination of RAID 1 plus RAID 0, hence the name (RAID 1+0). You duplicate all the drives using RAID 1; and then you group a number of individual drives into a larger single RAID 0 "drive".