I've been setting up my first unRaid box. it's has come to the point where I am slowly migrating data from my RAID 10 server to the unraid drives, my current set up is.

 

UnRAID - 2 x 2TB Drives (No parity until I transfer everything over)

RAID 10 - 8 x 2TB Drives

 

My question is, after I finish the migrating, and add the other 8 Drives to the unraid array, will the files I copied over with split levels be automatically transfered between the disks after I add those disks to the split?

 

Or will they reside on the original 2 Disks I had in the array, and continue to split on the other 8 disks I add after, becuase once I finish migrating, the 2 disks that were originally in the unraid array will be pretty much filled up.

Unraid never moves files between array disks automatically. The only automatic move is from the cache disk to an array disk, which disk it moves to is governed by your split level, free space, allocation, etc rules. Any reorganization or re-balancing will need to be done manually, but you can use the cache disk function to help, at the cost of temporarily putting your data at risk while it resides on an unprotected disk (cache drive). The fact that you chose to transfer data without parity means you must have a high tolerance for losing data, since everything you move is unprotected right now, so using the cache disk to re-balance fits your current risk tolerance. I hope you have backups of all your data. 

Perfect thanks, and everything I need protected is protected via another server :].